Lathem Time Systems Clock DDC2 User Manual

Digital Display Wall Clock  
DDC2 / DDC4 Series  
Installation &  
User's Guide  
Table of Contents  
3-Wire minute Impulse (59th Minute) .......................................................................................................24  
3-Wire Minute Impulse (59th Minute With 12 Hour Correction)..............................................................25  
Stromberg Synchronous Wired (56th Minute)...........................................................................................35  
3-Wire Minute Impulse (58th Minute).......................................................................................................41  
3-Wire Minute Impulse (44th Minute).......................................................................................................42  
2-Wire Reverse Polarity Minute Impulse (59th Minute) ...........................................................................43  
Page 1  
Digital Display Wall Clock Guide  
Introduction  
The Digital Display Series Wall Clocks are designed with 2-inch or 4-inch red LED displays that can be  
viewed from great distances; the 4-inch model as far away as 100 feet, the 2-inch model from as far away  
as 50 feet. The bright red display shows the hour and minutes and can be configured for a 12 or 24 hour  
format. By the setting of internal DIP switches, the DDC Series Wall Clocks can be configured to run as  
"stand-alone" or to replace many analog secondary clocks that may be hard to find or no longer available.  
The DDC Series Wall Clocks can be synchronized from the Lathem LTR4-512 or LTR8-512 Master, LTR0  
mini:master, Terminal Manager Software or the OMNI:CHRON Time Clock, using an RS485 correction  
signal.  
The DDC Series Wall Clocks with the optional DDC-TC Timer Control Panel allow the DDC Series Wall  
Clocks to act as a count up or count down timer as well as displaying the normal time. The optional Timer  
Control Panel is required to use this feature.  
The DDC Series Wall Clocks can be mounted directly to a wall, to a single gang outlet box or, with  
optional mounting kits, as double-faced units from the wall or ceiling.  
During power failures, a 9-Volt alkaline battery (not supplied) can maintain the DDC Series Wall Clock's  
internal time keeping (although the display is blank during power failures).  
Clock Operation  
When the Digital Display Series Wall Clocks are set to operate as stand-alone or synchronous wired  
secondary clocks, the time base is derived from the AC power source. The frequency (50Hz or 60Hz) is  
automatically detected when power is applied. The clocks then initialize to 12:00AM and maintain time by  
counting the line frequency. Corrective clocks will begin synchronization routines. Accuracy is related  
directly to the accuracy of the line frequency. With the DDC-TC option, the Digital Display Series Wall  
Clocks can act as a count up or count down timer as well as running as a stand-alone or synchronous wired  
secondary clock.  
When the Digital Display Series Wall Clocks are set to operate as impulse secondary clocks, the master  
clock controls time totally. Time will only advance when pulses are received from the master clock. Should  
the master clock lose power, the wall clocks would hold at the time that the last pulse was received until  
power to the master clock is restored and pulses continue. With the DDC-TC option, the Digital Display  
Series Wall Clocks can act as a count up or count down timer as well as running as an impulse secondary  
clock.  
 
Digital Display Wall Clock Guide  
Page 2  
About this Manual  
This manual will guide you through the installation, setup and wiring of your DDC Series Wall Clock. This  
manual covers the four available DDC Series models. The available models and their descriptions are:  
DDC2-RS / DDC4-RS  
Equipped with a 2-inch or 4-inch display, these models can operate as a stand-  
alone, a secondary clock to virtually any master controlled system or can be  
synchronized with the RS485 signal from the Lathem LTR4-512 or LTR8-512  
Master, LTR0 mini:master, Terminal Manager Software* or the OMNI:CHRON  
Time Clock.  
DDC2-RS-24 / DDC4-RS-24  
Same as above, models with the "-24" suffix have an optional power  
transformer that allows for 24VAC operation. These models are  
designed to be powered from an external, 24VAC-power supply for use  
in installations where local 115VAC power may not available.  
* The Lathem SWIFT-485 plus is required for RS485 synchronization.  
 
Page 3  
Digital Display Wall Clock Guide  
Optional Accessories  
VSE0050  
SAM0626  
SAM0630  
SAM0625  
VSE0052  
Power Cord, 6 feet. DDC Series Wall Clocks are shipped without power cords.  
Double Ceiling Mount Kit for DDC2 or DDC4 Series  
Double Wall Mount Kit for DDC2 Series  
Double Wall Mount Kit for DDC4 Series  
Mounting Bracket for 3510 Hz Electronic Receiver. (DDC4 only, installer must  
use optional method to mount Receiver outside the DDC2 if Receiver is used)  
(Receiver not included)  
DDC-TC  
Timer Control Panel to use the DDC2/4 Series as a count up/down timer  
LTR4-512  
LTR8-512  
LTR8-512M  
Master Clocks capable of synchronizing the DDC Series Wall Clocks as well as  
many other brands and types of wall clocks. Available configurations include 8,  
6, 4 and 2 bell circuits  
Mlink  
Master Link software for remote programming of the LTR8-512 and LTR8-  
512M Master Clocks  
SWIFT-485 plus  
RS232 to RS485 signal converter for use with Master Link to extend the  
distance of Master Clocks up to 4000'.  
 
Digital Display Wall Clock Guide  
Page 4  
SAM0626 Kit (left) Includes:  
1 - Mounting Plate Assembly  
8 - #10 Hex Nuts  
2 - Chase Nipples  
4 - #10 Screws 8 - #10 Lock Washers  
SAM0630 Kit (middle) Includes:  
1 - Mounting Plate Assembly  
2 - Modified End Caps  
2 - Chase Nipples  
4 - #10 Screws  
8 - #10 Lock Washers  
4 - #10 Hex Nuts  
SAM0625 Kit (right) Includes:  
1 - Mounting Plate Assembly  
2 - Modified End Caps  
1 - End Cap Support  
2 - Chase Nipples  
4 - #10 Screws  
4 - #6 Lock Washers  
8 - #10 Lock Washers  
4 - #6 Hex Nuts  
4 - #10 Hex Nuts  
4 - #6 Screws  
Page 5  
Digital Display Wall Clock Guide  
Configuring the DDC Series Wall Clock  
Setting the DIP Switches - DDC2 / DDC4 Series  
DDC2  
Remove the four phillips head screws from the left or the right end cap and remove. Slide the lens and  
circuit board assembly out of the case. Place the lens aside and carefully flip the circuit board assembly  
over and lay it face down on a clean, smooth work surface. Locate switch S1near the center of the circuit  
board and set the DIP switches (See figure1below) according to Tables 1, 2 and 3 on the following page for  
the proper configuration. Slide the lens and circuit board assembly back into the case, replace the end cap  
and secure with the four phillips head screws.  
DDC4  
Remove the two phillips head screws from the left or the right end cap and remove. Slide the front panel  
assembly out of the case. Carefully flip the front panel assembly over and lay it face down on a clean,  
smooth work surface. Locate switch S1near the center of the circuit board and set the DIP switches (See  
figure1below) according to Tables 1, 2 and 3 on the following page for the proper configuration. Slide the  
front panel display back into the case, replace the end cap and secure with the two phillips head screws.  
Switch S1  
1
2
3
4
5
7
6
8
Switch 8  
12 or 24 Hour Format  
Default Shown - 12 Hour  
OPEN  
Switches 1 - 5  
Secondary Clock Type  
Switches 6 & 7  
Baud Rate  
Default Shown - Stand Alone  
Default Shown - 9600 Baud  
= Depressed Side of Switch  
Figure 1  
 
Digital Display Wall Clock Guide  
Page 6  
DIP Switch Settings  
Table 1 - S1 (1-5) Secondary Clock Correction  
1
2
3
4
5
Secondary Clock Selection  
*=Factory Default  
0=Closed  
1=Open  
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
Stand Alone *  
3-Wire Synchronous  
3-Wire Minute Impulse (59th Minute)  
3-Wire Minute Impulse (59th Minute) With 12 Hour Correction  
Standard Electric Synchronous  
Standard Electric AR-2A - 2-Wire Dual Voltage  
Standard Electric AR-2 - 2-Wire Dual Voltage  
Cincinnati D8, Honeywell ST402A, Faraday Synchronous  
Simplex 59th Minute Dual Motor  
Simplex 45th Minute Dual Motor  
Edwards Dual Motor  
Standard Electric AR-3 - 3-Wire Minute Impulse  
National Synchronous Wired  
Stromberg Synchronous Wired  
Cincinnati D1  
Cincinnati D6, Edwards 2406  
2-Wire Impulse Alternating (24VDC)  
Electronic Coded (3510 Hz Receiver Required)  
Straight Frequency (3510 Hz Receiver Required)  
3-Wire Minute Impulse (58th Minute)  
3-Wire Minute Impulse (44th Minute)  
2-Wire Reverse Polarity Minute Impulse (59th Minute)  
Table 2 - S1 (6-7) RS 485 Baud Rate  
Baud Rate  
0=Closed 1=Open  
1200 Baud  
Table 3 - S1 (8) 12 / 24 Hour Display  
12 / 24 Hour Display  
0=Closed 1=Open  
6
7
8
0
1
0
1
0
0
1
1
1
0
12 Hour *  
24 Hour  
2400 Baud  
4800 Baud  
9600 Baud *  
Note: When switches 1-5 are set for any  
secondary type other than Stand-Alone, the  
display is forced to 12 Hour and the PM  
indicator does not illuminate.  
 
Page 7  
Digital Display Wall Clock Guide  
Configuring RS485 Communications - DDC2/4-RS Series  
When multiple DDC2 (4)-RS Series Wall Clocks are installed as slave units to either the Lathem LTR4-  
512 or LTR8-512 Master, LTR0 Mini-Master, Terminal Manager Software or the OMNI:CHRON Time  
Clock, the last clock on the line must have a shunt installed over both pins at position J2 (see figure 2, page  
9). When shipped, the shunt is placed over only one pin of position J2 in an "open" setting. It is necessary  
to place the shunt over both pins of position J2 and create a "closed" setting for the last clock on the line.  
DDC2-RS  
Remove the four phillips head screws from the left or the right end cap and remove. Slide the lens and  
circuit board assembly out of the case. Place the lens aside and carefully flip the circuit board assembly  
over and lay it face down on a clean, smooth work surface. Locate position J2 on the left, upper side of the  
back of the circuit board assembly (see figure 2, page 9). Lift the shunt straight up off the single pin of  
position J2. Align the shunt to cover both pins of position J2 and press firmly into place. Slide the lens and  
circuit board assembly back into the case, replace the end cap, and secure with the four phillips head  
screws.  
DDC4-RS  
Remove the two phillips head screws from the left or the right end cap and remove. Slide the front panel  
assembly out of the case. Carefully flip the front panel assembly over and lay it face down on a clean,  
smooth work surface. Locate position J2 on the left, upper side of the back of the front panel. (See figure 2,  
page 9) Lift the shunt straight up off the single pin of position J2. Align the shunt to cover both pins of  
position J2 and press firmly into place. Slide the front panel display back into the case, replace the end cap  
and secure with the two phillips head screws.  
Note: Only the LAST clock on the line needs position J2 "closed". Leave all other clocks "open".  
Battery Usage - DDC2 / DDC4 Series  
Depending on the secondary selection type, the 9-Volt alkaline battery (not included) performs different  
functions and may be required for proper operation.  
DDC2/4-RS / DDC2/4-RS-24  
When used as a secondary type clock the 9-Volt alkaline battery (not included) will retain the time that the  
power failure occurred, although the display will go blank. When power is restored, correction signals from  
the master clock will advance the wall clock to the proper time. When used as a secondary type clock in  
systems that do not provide a 12-Hour correction signal, the 9-Volt alkaline battery (not included) is  
required for proper operation. Without the 9-Volt alkaline battery (not included), the wall clock will reset to  
12:00 AM after power resumes and will not receive the proper signal from the master clock to fully correct.  
 
Digital Display Wall Clock Guide  
Page 8  
When used as a RS485 clock, the master clock will send a signal to the wall clock every minute. The 9-  
Volt alkaline battery (not included) is optional in these types of installations.  
Battery Installation - DDC2 / DDC4 Series  
DDC2  
Remove the four phillips head screws from the left or the right end cap and remove. Slide the lens and  
circuit board assembly out of the case. Place the lens aside and carefully flip the circuit board assembly  
over and lay it face down on a clean, smooth work surface. Locate the Battery Cradle on the upper right  
corner of the circuit board assembly. (See figure 2, page 9) Slide the battery into the cradle making sure the  
Positive and Negative connections of the battery and cradle match. Snap the battery onto the connections  
located inside the battery cradle. Slide the lens and circuit board assembly back into the case, replace the  
end cap and secure with the four phillips head screws.  
DDC4  
Remove the two phillips head screws from the left or the right end cap and remove. Slide the front panel  
assembly out of the case. Carefully flip the front panel assembly over and lay it face down on a clean,  
smooth work surface. Locate the Battery Cradle on the upper right corner of the circuit board assembly.  
(See figure 2, page 9) Slide the battery into the cradle making sure the Positive and Negative connections of  
the battery and cradle match. Snap the battery onto the connections located inside the battery cradle. Slide  
the front panel display back into the case, replace the end cap and secure with the two phillips head screws.  
Power Cord Installation - DDC2/4-RS  
Note: This section refers only to the 115VAC models. Applying power other than 24VAC to models DDC2-  
RS-24 or DDC4-RS-24 WILL CAUSE DAMAGE and void the warranty. See Appendix B for proper wiring  
of these models.  
DDC2-RS  
Remove the four phillips head screws from the left or the right end cap and remove. Slide the lens and  
circuit board assembly out of the case. Place the lens aside and carefully flip the circuit board assembly  
over and lay it face down on a clean, smooth work surface. Remove one of the vent caps from the case of  
the wall clock and route the power cord through it to the back of the circuit board assembly. (If the power  
cord will be routed through the back-of-the-clock conduit access, route the cord through the gang box and  
conduit access hole to the back of the circuit board assembly). Strip away 1/2" of the protective shield from  
each wire of the power cord. Locate the two black wires leading from J1 (see figure 2, page 9) and attach  
the AC In line of the cord to one and the AC Return line to the other. (normally black is AC In and white is  
 
Page 9  
Digital Display Wall Clock Guide  
AC Return) Attach the ground wire of the cord (normally green) to the green ground screw located on the  
inside back of the case. Slide the lens and circuit board assembly back into the case, replace the end cap  
and secure with the four phillips head screws.  
DDC4-RS  
Remove the two phillips head screws from the left or the right end cap and remove. Slide the front panel  
assembly out of the case. Carefully flip the front panel assembly over and lay it face down on a clean,  
smooth work surface. Remove one of the vent caps from the case of the wall clock and route the power  
cord through it to the back of the display panel. (If the power cord will be routed through the back-of-the-  
clock conduit access, route the cord through the gang box and conduit access hole to the back of the circuit  
board assembly). Strip away 1/2" of the protective shield from each wire of the power cord. Locate the two  
black wires leading from J1 (see figure 2, page 9) and attach the AC In line of the cord to one and the AC  
Return line to the other (normally black is AC In and white is AC Return). Attach the ground wire of the  
cord, (normally green) to the green ground screw located on the inside back of the case. Slide the front  
panel display back into the case, replace the end cap and secure with the two phillips head screws.  
Wiring Installation - DDC2/4-RS Series  
Secondary Wiring  
The DDC Wall Clock comes with a detachable wiring harness to make installation easier. The wiring  
harness can be removed from the back of the main circuit board at position J1 as shown in figure 2 so  
wiring from the master clock can be attached to the wiring harness with the clock's Electronic Assembly  
removed. The leads from the wiring harness should be connected as shown in the diagrams in Appendix A.  
RS485 Wiring  
The DDC Wall Clock comes with a detachable wiring block to make installation easier. The wiring block  
can be removed from the back of the main circuit board at position JP4 as shown in figure 2 so wiring from  
the master clock can be attached without the need of holding the Wall Clock itself. Wiring should be  
connected as shown in the diagrams in Appendix C.  
DDC-TC Wiring  
The DDC Wall Clock comes with a detachable wiring block to make installation easier. The wiring block  
can be removed from the back of the main circuit board at position JP2 as shown in figure 2 so wiring from  
the Timer Control Panel can be attached without the need of holding the Wall Clock itself. Wiring should  
be connected as shown in the diagrams in Appendix D.  
 
Digital Display Wall Clock Guide  
Page 10  
Replacing an Existing DDC4 Wall Clock  
When replacing an older style DDC4 Wall Clock it will be necessary to remove any connectors used by the  
older style clock and attach the wires to the new DDC Series Wall Clock as described above.  
Board Layout Diagram  
Fly Lead  
Jumper  
Connector  
J1  
9VDC Alkaline Battery  
Cradle  
J2  
DIP Switch  
S1  
Hours  
Minutes  
Up  
-
+
1
2
3
4
5
7
6
8
OPEN  
JP2  
JP4  
Lathem Time Corp.  
DDC2\4  
Ground  
Beeper  
D-  
(E-PROM)  
JP3  
D+  
JP1  
J4  
J3  
J2  
J2  
Factory Default  
Off  
Install shunt on  
last clock for RS485 connections  
Figure 2  
 
Page 11  
Digital Display Wall Clock Guide  
Mounting - DDC2 / DDC4 Series  
The DDC Series Wall Clocks can be mounted directly to a wall, to a single gang outlet box, double hung  
from the wall or double hung from the ceiling. When deciding where the clock will be mounted, keep in  
mind that 115VAC power may be required depending on the installation type.  
See page 14, figure 3.  
Mounting to a Wall  
Tools required for mounting the clock:  
Drill with a 5/16" bit  
Hammer  
Phillips head screwdriver  
Wall anchors  
Pencil  
DDC2  
»
After deciding the location where the clock will be mounted, make two marks 7" apart and  
horizontal.  
Note: If mounting near a ceiling, make sure the holes are at least 2 1/4" away from the ceiling.  
Note: Make sure you have at least 10 1/2" of side clearance on one side in order to remove the lens and  
circuit board assembly.  
»
»
»
»
Drill a 5/16" hole at each mark  
Insert a wall anchor in each hole and tap it flush to the wall with the hammer.  
Insert a screw into each wall anchor leaving 1/4" exposed.  
Remove the four phillips head screws from the left or the right end cap and remove. Slide the lens  
and circuit board assembly out of the case and set aside.  
»
»
Line up the two keyholes on the back of the case and slip over the two screws and tighten  
securely. ( The lower mounting holes can be marked at this point, the case removed, holes drilled  
and wall anchors installed if so desired)  
Remove the desired vent cap that any required wiring will route through. (If the wiring will be  
installed through the back-of-the-clock conduit access, route the fly leads of the clock's Cable  
Harness Assembly from the interior of the clock through the hole in the Clock's rear plate. Use  
wire nuts or crimp connectors to join these leads with the power and synch signal cable in the  
gang box behind the clock to eliminate possible snagging when the circuit board assembly is  
removed or replaced. If RS-485 signaling is used, attach the signal pair to the mini Terminal Block  
Plug and pass the cable from behind the clock, through the hole into the clock's interior).  
Route the 6-position plug (and optional RS485 cable) to the circuit board assembly and attach.  
»
 
Digital Display Wall Clock Guide  
Page 12  
»
Slide the lens and circuit board assembly back into the case, replace the end cap and secure with  
the four phillips head screws.  
DDC4  
»
After deciding the location where the clock will be mounted, make two marks 12" apart and  
horizontal.  
Note: If mounting near a ceiling, make sure the holes are at least 2 1/4" away from the ceiling.  
Note: Make sure you have at least 16" of side clearance on one side in order to remove the front panel.  
»
»
»
»
Drill a 5/16" hole at each mark  
Insert a wall anchor and tap it flush to the wall with the hammer.  
Insert a screw into each wall anchor leaving 1/4" exposed.  
Remove the two phillips head screws from the left or the right end cap and remove. Slide the front  
panel assembly out of the case and set aside.  
»
»
Line up the two keyholes on the back of the case and slip over the two screws and tighten  
securely. ( The lower mounting holes can be marked at this point, the case removed, holes drilled  
and wall anchors installed if so desired)  
Remove the desired vent cap that any required wiring will route through. (If the wiring will be  
installed through the back-of-the-clock conduit access, route the fly leads of the clock's Cable  
Harness Assembly from the interior of the clock through the hole in the Clock's rear plate. Use  
wire nuts or crimp connectors to join these leads with the power and synch signal cable in the  
gang box behind the clock to eliminate possible snagging when the circuit board assembly is  
removed or replaced. If RS-485 signaling is used, attach the signal pair to the mini Terminal Block  
Plug and pass the cable from behind the clock, through the hole into the clock's interior).  
Route the 6-position plug (and optional RS485 cable) to the circuit board assembly and attach.  
Slide the front panel display back into the case, replace the end cap and secure with the two  
phillips head screws.  
»
»
Mounting to a Single Gang Box  
Two mounting holes have been located in the center of the case 2 1/4" apart for mounting to a single gang  
wall box. A 7/8" hole has been placed between the mounting holes that will accept conduit if desired.  
See page 14, figure 3.  
 
Page 13  
Digital Display Wall Clock Guide  
DDC2  
Note: If mounting near a ceiling, make sure the top of the single gang box is at least 2 1/4" away from the  
ceiling.  
Note: Make sure you have at least 10 1/2" of side clearance on one side in order to remove the lens and  
circuit board assembly.  
»
»
Remove the four phillips head screws from the left or the right end cap and remove. Slide the lens  
and circuit board assembly out of the case and set aside.  
Remove the desired vent cap that any required wiring will route through. (If the wiring will be  
installed through the back-of-the-clock conduit access, route the fly leads of the clock's Cable  
Harness Assembly from the interior of the clock through the hole in the Clock's rear plate. Use  
wire nuts or crimp connectors to join these leads with the power and synch signal cable in the  
gang box behind the clock to eliminate possible snagging when the circuit board assembly is  
removed or replaced. If RS-485 signaling is used, attach the signal pair to the mini Terminal Block  
Plug and pass the cable from behind the clock, through the hole into the clock's interior).  
Line the two holes in the case up to the single gang box and insert proper screws for the single  
gang box and tighten securely.  
»
»
»
Route the 6-position plug (and optional RS485 cable) to the circuit board assembly and attach.  
Slide the lens and circuit board assembly back into the case, replace the end cap and secure with  
the four phillips head screws.  
DDC4  
Note: If mounting near a ceiling, make sure the top of the single gang box is at least 2 1/4" away from the  
ceiling.  
Note: Make sure you have at least 16" of side clearance on one side in order to remove the front panel.  
»
»
Remove the two phillips head screws from the left or the right end cap and remove. Slide the front  
panel assembly out of the case and set aside.  
Remove the desired vent cap that any required wiring will route through. (If the wiring will be  
installed through the back-of-the-clock conduit access, route the fly leads of the clock's Cable  
Harness Assembly from the interior of the clock through the hole in the Clock's rear plate. Use  
wire nuts or crimp connectors to join these leads with the power and synch signal cable in the  
gang box behind the clock to eliminate possible snagging when the circuit board assembly is  
removed or replaced. If RS-485 signaling is used, attach the signal pair to the mini Terminal Block  
Plug and pass the cable from behind the clock, through the hole into the clock's interior).  
Line the two holes in the case up to the single gang box and insert proper screws for the single  
gang box and tighten securely.  
»
»
Route the 6-position plug (and optional RS485 cable) to the circuit board assembly and attach.  
 
Digital Display Wall Clock Guide  
Page 14  
»
Slide the front panel display back into the case, replace the end cap and secure with the two  
phillips head screws.  
Vent holes  
For single  
gang box  
mount  
For 1/2"  
conduit  
Keyholes for  
wall mount  
Figure 3  
Double Mount - Wall  
DDC2 Requires optional mounting kit (SAM0630)  
DDC4 Requires optional mounting kit (SAM0625)  
Tools required for mounting the clock:  
Flat blade screwdriver  
Phillips head screwdriver  
15/16" open end wrench  
The double wall mount plate attaches to a double or single gang box installed securely in the wall. Required  
wiring should be available through the gang box at time of installation.  
»
»
Remove the two chase nipples from the mounting plate posts.  
Run the required wiring from the gang box through one of the mounting posts of the mounting  
plate.  
»
Secure the mounting plate securely to the gang box with the proper screws. (not supplied)  
 
Page 15  
Digital Display Wall Clock Guide  
Note: The long dimension of the mounting plate must be perpendicular to the ground to assure proper  
alignment of wall clocks.  
See page 15, figure 4 for DDC2 details.  
See page 16, figure 5 for DDC4 details.  
DDC2 (Double Mount - Wall)  
»
Remove the four phillips head screws from the left and the right end caps of the two DDC2 clocks  
and remove. Slide the lenses and circuit board assemblies out of the cases and set aside.  
Place the two DDC2 clocks back to back and secure by inserting a #10 screw through the two key  
holes and the two lower mounting holes using lock washers and nuts supplied with the mounting  
kit.  
»
»
Attach the modified end caps to the end of the clocks that will be attached to the wall mount plate  
using the original end cap screws.  
»
»
Run the required wiring through the matching hole in the modified end cap.  
Line the two posts from the mounting plate up with the two holes of the modified end caps. Insert  
the chase nipples through the holes of the modified end caps and secure to the mounting plate with  
a 15/16" wrench.  
»
»
»
Slide the circuit board assemblies in partially. Secure the required wiring and install the battery if  
used.  
Slide the circuit board assemblies in fully along with the lenses. Install the end caps and secure  
each with its four screws.  
Discard or store the two original end caps the modified end caps replaced.  
mounting plate  
modified end caps  
chase nipples  
DDC2 cases  
#10 hex nuts  
#10 lock washers  
#10 lock washers  
#10 screws  
Figure 4  
 
Digital Display Wall Clock Guide  
Page 16  
DDC4 (Double Mount - Wall)  
»
Remove the two phillips head screws from the left and the right end caps of the two DDC4 clocks  
and remove. Slide the front panel assemblies out of the cases and set aside.  
Place the two DDC4 clocks back to back and secure by inserting a #10 screw through the two key  
holes and the two lower mounting holes using lock washers and nuts supplied with the mounting  
kit.  
»
»
»
»
Attach the modified end cap to the end of the clocks that will be attached to the wall mount plate  
using the original end cap screws.  
Align the holes of the end cap support plate with the holes in the modified end cap and secure with  
4 #6 phillips head screws (supplied)  
Line the two posts from the mounting plate up with the two holes of the modified end cap. Insert  
the chase nipples through the holes of the modified end cap and secure to the mounting plate with  
a 15/16" wrench.  
»
Slide the front panel assemblies in partially. Secure the required wiring and install the battery if  
used.  
»
»
Slide the front panel assemblies in fully. Install the end caps and secure each with its two screws.  
Discard or store the two original end caps the modified end cap replaced.  
mounting plate  
modified end caps  
DDC4 cases  
end cap support  
#10 hex nuts  
#10 lock washers  
chase nipples  
#10 lock washers  
#10 screws  
Figure 5  
 
Page 17  
Digital Display Wall Clock Guide  
Double Mount - Ceiling  
Requires optional mounting kit (SAM0626)  
Tools required for mounting the clock:  
Flat blade screwdriver  
Phillips head screwdriver  
15/16" open end wrench  
The double ceiling mount plate attaches to a double or single gang box installed securely in the ceiling.  
Required wiring should be available through the gang box at time of installation.  
»
»
Remove the two chase nipples from the mounting plate posts.  
Run the required wiring from the gang box through one of the mounting posts of the mounting  
plate.  
»
Secure the mounting plate securely to the gang box with the proper screws. (not supplied)  
Note: When mounting DDC2 clocks, the short side of the mounting plate must be parallel to the long side  
of the clocks. When mounting DDC4 clocks, the long side of the mounting plate must be parallel to the long  
side of the clocks.  
See page 18, figure 6 for DDC2 details.  
See page 19, figure 7 for DDC4 details  
 
Digital Display Wall Clock Guide  
Page 18  
DDC2 (Double Mount - Ceiling)  
Note: Make sure you have at least 10 1/2" of side clearance on one side in order to remove the lens and  
circuit board assembly.  
»
»
Remove the four phillips head screws from the left and the right end caps of the two DDC2 clocks  
and remove. Slide the lenses and circuit board assemblies out of the cases and set aside.  
Place the two DDC2 clocks back to back and secure by inserting a #10 screw through the two key  
holes and the two lower mounting holes using lock washers and nuts supplied with the mounting  
kit. Note: At this point, if the DDC2 clocks will be mounted too near a wall on one side to secure  
the end caps, install the "wall side" end caps now.  
»
»
Remove the center vent cap from the top of each DDC2 clock.  
Line the two posts from the mounting plate up with the vent holes of the DDC2 clocks. Insert the  
chase nipples through the vent holes and secure to the mounting plate with a 15/16" wrench.  
Slide the circuit board assemblies in partially. Secure the required wiring and install the battery if  
used.  
Slide the circuit board assemblies in fully along with the lenses. Install the end caps and secure  
each with its four screws.  
»
»
Note: When mounting DDC2 clocks, the  
short side of the mounting plate must be  
parallel to the long side of the clocks  
mounting plate  
#10 hex nuts  
DDC2 cases  
chase nipple  
#10 lock washers  
chase nipple  
#10 screws  
#10 lock washers  
Figure 6  
Page 19  
Digital Display Wall Clock Guide  
DDC4 (Double Mount - Ceiling)  
Note: Make sure you have at least 16" of side clearance on one side in order to remove the front panel  
assembly.  
»
»
Remove the two phillips head screws from the left and the right end caps of the two DDC4 clocks  
and remove. Slide the front panel assemblies out of the cases and set aside.  
Place the two DDC4 clocks back to back and secure by inserting a #10 screw through the two key  
holes and the two lower mounting holes using lock washers and nuts supplied with the mounting  
kit. Note: At this point, if the DDC4 clocks will be mounted too near a wall on one side to secure  
the end caps, install the "wall side" end caps now.  
»
»
Remove the center vent cap from the top of each DDC4 clock.  
Line the two posts from the mounting plate up with the vent holes of the DDC4 clocks. Insert the  
chase nipples through the vent holes and secure to the mounting plate with a 15/16" wrench.  
Slide the front panel assemblies in partially. Secure the required wiring and install the battery if  
used.  
»
»
Slide the front panel assemblies in fully. Install the end caps and secure each with its two screws.  
Note: When mounting DDC4 clocks, the  
long side of the mounting plate must be  
parallel to the long side of the clocks  
mounting plate  
#10 hex nuts  
DDC4 cases  
chase nipple  
chase nipple  
#10 screws  
#10 lock washers  
Figure 7  
 
Digital Display Wall Clock Guide  
Page 20  
Setting the Time  
Time is set on the DDC Series Wall Clocks by depressing buttons located on the left side of the front panel.  
There are two setting buttons, "H" for hour and "M' for minute.  
»
To advance the hour or minute to the correct time one digit at a time press and release the proper  
button. Do this as many times as required until the correct time is displayed. When setting the  
hour, if the display is set to 12 Hour, a "dot" in the upper left corner of the display represents the  
PM hours.  
»
To rapidly advance the hour or minute press and hold the proper button. Release the button when  
the correct time is displayed. When setting the hour, if the display is set to 12 Hour, a "dot" in the  
upper left corner of the display represents the PM hours.  
Note: Setting the minutes past 59 will not cause the hour to advance.  
Note: Avoid using sharp or pointed objects to set the time as damage to the buttons may occur. A standard  
pencil eraser is suggested.  
Time Formats  
The DDC2 / DDC4 Series Wall Clocks can be set to display in 12 Hour or 24 Hour format. When in 12-  
Hour format, a round LED in the upper left corner of the display indicates PM hours. When in 24 Hour  
format, the hours are displays in Military style. To set the display format, use Table 3 on page 4 to set  
switch 8 of S1.  
Note: When switches 1-5 are set for any secondary type other than Stand-Alone, the display is forced to 12  
Hour and the PM indicator does not illuminate.  
12 Hour Format  
H
H
M
M
AM  
PM  
24 Hour Format  
H
M
 
Page 21  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Appendix A - DDC2-RS / 4-RS Secondary Clock Wiring Diagrams  
Note: See Appendix B for DDC2-RS-24 / DDC4-RS-24 wiring.  
Stand-Alone (115VAC)  
H
M
115VAC  
Local  
Power  
GRND  
AC IN  
AC RTN  
Hour and Minutes must be set manually. Use of a  
9Volt alkaline battery is recommended to avoid  
resets after power failures.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 22  
3-Wire Synchronous (115VAC)  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock will correct minutes hourly at HH:59 and  
hour and minutes twice daily at 5:59.  
Wiring applies to secondary wall clocks such as:  
Lathem type SS Cincinnati D10 IBM 77 Series  
Simplex 77 Series, 93-9, 91-9, 941-9, 943-9  
Stromberg 3000  
1
2
3
4
5
7
6
8
OPEN  
 
Page 23  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
3-Wire Synchronous (24VAC)  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
Return  
24VAC  
From  
Master Clock  
To  
Other Clocks  
Correction  
Clock will correct minutes hourly at HH:59 and  
hour and minutes twice daily at 5:59.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Wiring applies to secondary wall clocks such as:  
Lathem type SS Cincinnati D10 IBM 77 Series  
Simplex 77 Series, 93-9, 91-9, 941-9, 943-9  
Stromberg 3000  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 24  
3-Wire minute Impulse (59th Minute)  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
A
B
C
24VDC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
1
2
3
4
5
7
6
8
Wiring applies to secondary wall clocks such as:  
Lathem ISC 3-Wire  
Stromberg Impulse  
Standard Impulse  
Edwards Impulse  
Cincinnati D2, D4  
Faraday Impulse  
IBM 75 Series  
OPEN  
Simplex 75 Series, 91-4, 93-4, 941-4, 943-4  
 
Page 25  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
3-Wire Minute Impulse (59th Minute With 12 Hour Correction)  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
A
B
C
24VDC  
From  
Master Clock  
To  
Other Clocks  
Clock will correct minutes hourly at HH:58 and  
hour and minutes twice daily at 5:58.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Wiring applies to secondary wall clocks such as:  
1
2
3
4
5
7
6
8
Lathem ISC 3-Wire 12Hour  
Simplex 91, 941  
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 26  
Standard Electric Synchronous  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Clock will correct minutes hourly at HH:59 and  
hour and minutes twice daily at 5:12.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
 
Page 27  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Standard Electric AR-2A 2-Wire Dual Voltage  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
AB  
PC  
24VDC / 48VDC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock must be set to actual time. Use of a 9Volt  
alkaline battery is recommended to avoid resets  
after power failures.  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 28  
Standard Electric AR-2 2-Wire Dual Voltage  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
AB  
PC  
24VDC / 48VDC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock must be set to actual time. Use of a 9Volt  
alkaline battery is recommended to avoid resets  
after power failures.  
1
2
3
4
5
7
6
8
OPEN  
 
Page 29  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Synchronous Wired  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock will correct minutes hourly at HH:58 and  
hour and minutes twice daily beginning at 5:05.  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
Wiring applies to secondary wall clocks such as:  
Cincinnati D8  
Faraday  
Honeywell ST402A  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 30  
Simplex 59th Minute Dual Motor  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Clock must be set to proper hour. Clock will  
correct minutes hourly at HH:58. . Use of a 9Volt  
alkaline battery is recommended to avoid resets  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
 
Page 31  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Simplex 45th Minute Dual Motor  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock must be set to proper hour. Clock will  
correct minutes hourly at HH:45. . Use of a 9Volt  
alkaline battery is recommended to avoid resets  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 32  
Edwards Dual Motor  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock must be set to actual time. Use of a 9Volt  
alkaline battery is recommended to avoid resets  
after power failures.  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
 
Page 33  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Standard Electric AR-3 3-Wire Minute Impulse  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
24 VDC Pulse  
48 VDC Correction  
Common  
24VDC / 48VDC  
From  
Master Clock  
To  
Other Clocks  
Clock must be set to actual time. Use of a 9Volt  
alkaline battery is recommended to avoid resets  
after power failures.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 34  
National Synchronous Wired  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock will correct minutes hourly at HH:00 and  
hour and minutes twice daily at 6:00.  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
 
Page 35  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Stromberg Synchronous Wired (56th Minute)  
H
M
Run  
AC Return  
Correction  
115VAC  
From  
Master Clock  
To  
Other Clocks  
Clock will correct minutes hourly at HH:56 and  
hour and minutes twice daily at 11:56.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
For 24VAC applications, use  
wiring shown on page 18  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 36  
Cincinnati D1  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
A
24VDC / 60VDC  
From  
Master Clock  
To  
Other Clocks  
COMMON  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
1
2
3
4
5
7
6
8
OPEN  
 
Page 37  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Cincinnati D6, Edwards 2406  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
AB  
PC  
24-36VDC  
From  
Master Clock  
To  
Other Clocks  
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
I di  
d
d id  
f
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 38  
2-Wire Pulse Alternating (24VDC)  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
A
B
24VDC  
From  
Master Clock  
To  
Other Clocks  
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
Page 39  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
Electronic Coded  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
GRAY  
RED  
3510 Hz  
Reciever  
Requires 3510Hz receiver (not supplied)  
Set switches 1-5 of S1 as shown.  
Clock will correct minutes hourly at HH:57 and  
hour and minutes twice daily at 5:57.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 40  
Straight Frequency  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
GRAY  
RED  
3510 Hz  
Reciever  
Requires 3510Hz receiver (not supplied)  
Set switches 1-5 of S1 as shown.  
Clock will correct minutes hourly at HH:57 and  
hour and minutes twice daily at 5:57.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
Page 41  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
3-Wire Minute Impulse (58th Minute)  
H
M
GRND  
AC IN  
AC RTN  
115VAC  
Local  
Power  
A
B
C
24VDC  
From  
Master Clock  
To  
Other Clocks  
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS Wiring  
Digital Display Wall Clock Guide  
Page 42  
3-Wire Minute Impulse (44th Minute)  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
A
24VDC  
From  
Master Clock  
To  
B
Other Clocks  
C
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
Page 43  
Digital Display Wall Clock Guide  
DDC2 / 4-RS Wiring  
2-Wire Reverse Polarity Minute Impulse (59th Minute)  
H
M
GRND  
115VAC  
Local  
Power  
AC IN  
AC RTN  
AB  
PC  
24VDC  
From  
Master Clock  
To  
Other Clocks  
Clock must be set within 20 minutes of actual time  
for master to synchronize. Use of a 9Volt alkaline  
battery is recommended to avoid resets after power  
failures.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS -24 Wiring  
Digital Display Wall Clock Guide  
Page 44  
Appendix B - DDC2-RS-24 / DDC4-RS-24 Wiring  
The DDC2-RS-24 and the DDC4-RS-24 allow for 24VAC supplied from the Master Clock or Power  
Supply to power it for normal operation. These models can be used in installations where local 115VAC  
power may not be available. When shipped, the DDC2-RS-24 and DDC4-RS-24 have an optional power  
transformer that allows for 24VAC operation.  
The 24VAC power from the Master Clock or Power Supply should be connected to the two black wires  
leading from J1. (See figure 7 below for location of J1)  
Correction wiring should be applied according to the secondary type selection as shown in Appendix A.  
CAUTION: Applying any voltage higher than 24VAC to the input (two black leads  
from J1) WILL cause damage to the DDC2-RS-24 and DDC4-RS-24 clocks.  
Fly Lead  
Jumper  
Connecto
J1  
9VDC Alkaline Battery  
Cradle  
J2  
DIP Switch  
S1  
Hours  
Minutes  
Up  
-
+
1
2
3
4
5
7
6
8
OPEN  
Down  
JP2  
JP4  
Lathem Time Corp.  
DDC2\4  
Ground  
Beeper  
D-  
(E-PROM)  
JP3  
D+  
JP1  
J4  
J3  
Figure 7  
 
Page 45  
Digital Display Wall Clock Guide  
DDC2 / 4-RS -24 Wiring  
DDC2-RS-24 / DDC4-RS-24 Wiring  
H
M
Run  
AC Return  
Correction  
24VAC  
From  
Master Clock  
To  
Other Clocks  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS -485 Wiring  
Digital Display Wall Clock Guide  
Page 46  
Appendix C - RS485 Wiring Diagrams  
RS485 Data Format  
The data string that sends the time to the DDC2 / DDC4 Series Wall Clocks is formatted in such a manner  
that a utility can be written to achieve time updates from a personal computer. The following table shows  
the layout and explains each character.  
Data Format  
0#112233445566777Z,CR  
The data string is compiled of a total of 16 characters. These characters represent the following.  
0
Address byte  
#
Command for Time update  
Hex for Seconds (01-59)  
Hex for Minutes (00-59)  
Hex for Hour (00-23)  
Hex for Day of Week (Sunday = 0)  
Hex for Month (01-12)  
Hex for Date (01-31)  
11  
22  
33  
44  
55  
66  
777 Hex for Year offset from 1984 (000-127)  
Z
The Checksum (1's compliment of the mod-64 sum of all characters in the string except the CR and  
the Checksum)  
CR Carriage Return  
Transfer of the above string must be done at 9600 Baud, 8 Data Bits, 1 Stop Bit and No Parity.  
Requires the SWIFT-485 plus to convert the RS232 signal from the PC to RS485 to send data to the DDC  
Series Wall Clocks.  
Note: Lathem does not offer a utility to perform this function. This information is supplied so that a 3rd  
party may create such a utility.  
 
Page 47  
Digital Display Wall Clock Guide  
DDC2 / 4-RS -485 Wiring  
OMCII to DDC2-RS / 4-RS  
115VAC  
Local  
BLK  
Power  
BLK  
H
M
:
10  
OMC II  
To  
Other Clocks  
OMCII DB9 Female Plug  
DDC2-RS / 4-RS - JP4 Connector  
Pin  
Signal  
Signal  
JP4 Connection  
1
2
8
Transmit Data (-)  
Transmit Data (+)  
Signal Ground  
Transmit Data (-) D-  
Transmit Data (+) D+  
Signal Ground  
GND  
Cable should be RS232 twisted pair / CAT3 or CAT5 type.  
Maximum distance to last DDC Clock is 4000 feet.  
Last DDC Clock must have jumper installed on position J2.  
See page 8 for details.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC2 / 4-RS -485 Wiring  
Digital Display Wall Clock Guide  
Page 48  
LTR0 to DDC2-RS / 4-RS  
115VAC  
Local  
BLK  
Power  
BLK  
H
M
LTR 0  
To  
Other Clocks  
LTR0 Fly Leads  
DDC2-RS / 4-RS - JP4 Connector  
Wire  
Gray  
Signal  
Transmit Data (-)  
Signal  
Transmit Data (-) D-  
Transmit Data (+) D+  
JP4 Connection  
Orange Transmit Data (+)  
Black Signal Ground  
Signal Ground  
GND  
Cable should be RS232 twisted pair / CAT3 or CAT5 type.  
Maximum distance to last DDC Clock is 4000 feet.  
Last DDC Clock must have jumper installed on position J2.  
See page 8 for details.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
Page 49  
Digital Display Wall Clock Guide  
DDC2 / 4-RS -485 Wiring  
LTR4 / 8-512 to DDC2-RS / 4-RS  
115VAC  
Local  
Power  
BLK  
BLK  
H
M
1
LTR4 / 8-512  
To  
Other Clocks  
LTR4 / 8-512 Terminal Connections  
DDC2-RS / 4-RS - JP4 Connector  
Terminal #  
9 (D-)  
8 (D+)  
Signal  
Transmit Data (-)  
Transmit Data (+)  
Signal  
Transmit Data (-) D-  
Transmit Data (+) D+  
JP4 Connection  
Cable should be RS232 twisted pair / CAT3 or CAT5 type.  
Maximum distance to last DDC Clock is 4000 feet.  
Last DDC Clock must have jumper installed on position J2.  
See page 8 for details.  
Set switches 1-5 of S1 as shown.  
Indicates depressed side of switch  
1
2
3
4
5
7
6
8
OPEN  
 
DDC-TC Timer Control Panel  
Digital Display Wall Clock Guide  
Page 50  
Appendix D - DDC-TC Timer Control Panel  
Wiring  
The DDC-TC can be connected to the DDC Series Wall Clock with a 6 conductor CAT3 or CAT5 network  
cable. The DDC-TC can be mounted up to 200 feet from the DDC Series Wall Clock. The DDC-TC comes  
with 6 wire nuts to connect the network cable to the 6 control wires mounted on the back of the DDC-TC.  
The 6 control wires include Up, Down, Hours, Minutes, Beeper and Ground. To wire the DDC-TC to the  
DDC Series Wall Clock locate JP2 and JP4 on the back of the DDC display panel (see figure 2, page 10),  
pass the wire through a knockout at both the DDC-TC double-gang box (not included), the DDC Wall  
Clock and follow the diagram below.  
Rear View - Used for Reference  
Up  
Hours  
Down  
Minutes  
Beeper  
Ground  
JP2  
JP4  
Green  
Green / White  
Hours  
Hours  
Minutes  
Minutes  
Brown  
Up  
Up  
Brown / White  
Down  
Down  
Blue  
Ground  
Beeper  
Ground  
Beeper  
Blue / White  
D-  
CAT3 or CAT5 Cable - 200 feet maximum  
Wire colors may vary. Keep in pairs as shown  
D+  
DDC-TC Panel  
DDC Series Wall Clock  
 
Page 51  
Digital Display Wall Clock Guide  
DDC-TC Timer Control Panel  
Installation  
The DDC-TC mounts directly to a standard, double-gang wall box. (not included) Once the wiring has been  
attached, place the wires inside the double-gang wall box and mount the DDC-TC to the box with the four  
screws supplied with the DDC-TC by inserting them through the mounting holes and securing.  
Mounting Holes  
TIMER CONTROL  
Count Up  
Start 00:00  
Set Hours  
Quit  
Stop / Continue  
Count Down  
Start HH:MM  
Set Minutes  
Stop / Continue  
Mounting Holes  
 
DDC-TC Timer Control Panel  
Digital Display Wall Clock Guide  
Page 52  
Operation  
As a Count Up Timer  
To start the count:  
To pause the count:  
To continue the count:  
press Count Up  
press Stop / Continue  
press Stop / Continue  
To return to clock mode: press Quit  
As a Count Down Timer  
To set hours:  
press Set Hours (defualt is 00: )  
To set minutes:  
press Set Minutes (defualt is :00)  
press Count Down  
press Stop / Continue  
press Stop / Continue  
To start the count:  
To pause the count:  
To continue the count:  
To return to clock mode: press Quit  
Note: To pause and continue, press the corresponding Stop / Continue button that started the operation.  
In the Count Down mode, when 00:00 is reached, an audible tone will sound and the display will return to  
clock mode.  
When in Count Up or Count Down mode, when the time being counted is greater than 60 minutes the  
display will read HH:MM. When the time being counted reaches less than 60 minutes, the display will read  
MM:SS.  
 
Page 53  
Digital Display Wall Clock Guide  
Specifications  
Appendix E - LTR-GPS Satellite Receiver / Clock Synchronizer  
Lathem’s LTR-GPS is a Global Positioning Satellite receiver using 12-channels to access the accurate date  
and time signal transmitted each second by 24 satellites in geosynchronous orbit around the globe.  
The package includes an amplified GPS Antenna, which must be mounted out-doors or beneath a roof sky-  
light, facing skyward. An integrated cable links the Antenna to the LTR-GPS Receiver Module, which  
should be mounted in-doors.  
The Receiver Module verifies and reformats the received satellite data, and offers multiple synchronization  
protocol outputs:  
The RS-485 Output can directly synchronize up to 31 Lathem time products, up to 4000ft away, over a  
single twisted-pair from a user-provided Cat-3 or Cat-5 cable. The length of cable and number of  
synchronized devices can be further increased using Lathem’s “SWIFT485+” RS-485 Converter / Repeater.  
The supported products include:  
LTR-0  
DWA-S  
Master Clock 1-Clock Ctl  
Sonochron 1-Bell Ckt  
Master Clock 1-Clk + 2-Ckt  
Master Clock 1-Clk + 6-Ckt  
Master Clock w/ Modem  
2” Digital Wall Clock 115v  
2” Digital Wall Clock 24v  
4” Digital Wall Clock 115v  
4” Digital Wall Clock 24v  
LTR4-512  
LTR8-512  
LTR8-512M  
DDC2-RS  
DDC2-RS-24  
DDC4-RS  
DDC4-RS-24  
An included RS-232 interface provides a periodic “Time Stamp” transmission, “MM-DD-YYYY  
HH:MM:SS cr”, for use by computing systems having custom software to incorporate accurate date and  
time records in their applications: 9600,N,8,1. Use of this option requires Lathem cable, Part No.  
SAE0370, to be ordered separately.  
Simple DIP-Switch set-up enables the installer to specify local Time Zone, Daylight Savings Time  
corrections, and output formats. An LED indicator shows Signal Reception / Protocol Mode.  
The LTR-GPS may receive its power from an LTRx-512-series Master Clock, using 2nd cable pair, if the  
distance is less than 200ft; else, power is provided locally by a 9vAC Power Adapter.  
 
Warranty  
Digital Display Wall Clock Guide  
Page 54  
The LTR-GPS package includes:  
LTR-GPS Satellite Synchronizer  
115vAC, 2.7w, 50/60Hz Power Adapter  
Active GPS Antenna with 25ft. Cable  
Antenna Mounting Bracket and Hardware  
Installation and Set-Up Guide  
Separately, from Lathem, for Installer convenience:  
GPS-INSTALL-TOOLS: Battery / Beeper assemblies aid in Antenna positioning  
LTR-GPS Specifications:  
Size / Weight  
Power:  
Certificates:  
3.25”x 2”x6.6” / 1 lb.  
6-12vAC/DC, 300mA (max)  
FCC Part-15, ICES003  
Page 55  
Digital Display Wall Clock Guide  
Specifications  
Connecting to a Lathem DDC2-RS or DDC4-RS Digital Clock  
DDC2-RS / DDC4-RS  
 
Warranty  
Digital Display Wall Clock Guide  
Page 56  
Appendix F - Specifications  
Dimensions  
DDC2  
DDC4  
4 7/8" H X 10 1/4" W X 3 1/8" D  
12.4 cm H X 26.2 cm W X 7.9 cm D  
6 3/4" H X 15 1/2" W X 3 1/8" D  
17.1 cm H X 39 cm W X 7.9 cm D  
Weight  
Display  
Housing  
DDC2  
DDC4  
3.2 lbs (1.451 kg)  
9 lbs. (4.086 kg)  
DDC2  
DDC4  
1 3/4-Inch Red 7 Segment LED  
3 3/4-Inch Red 7 Segment LED  
DDC2  
DDC4  
Extruded aluminum main case with black textured paint, red  
lexan panel; steel end caps with black textured paint.  
Extruded aluminum main case with black textured paint, steel  
front panel with black textured paint; molded plastic end caps  
with black texture.  
Line Power  
DDC2 / DDC4  
115VAC, 80mA typical  
220VAC, 80mA typical (optional)  
DDC2-RS-24 /  
DDC4-RS-24  
24VAC, 400mA typical  
Standby Power  
Environment  
DDC2 / DDC4  
DDC2 / DDC4  
9VDC, 1.2mA Alkaline Battery (not included)  
32o to 150 o F (0 o to 65 o C)  
95% Relative Humidity (non-condensing)  
Correction Signal  
115VAC, 6.5mA  
24VDC, 16mA  
48VDC, 40mA  
60VDC, 56mA  
24VAC, 6.5mA  
Mounting  
DDC2 / DDC4  
Wall (surface)  
Single Gang Box (surface)  
Double Face (wall or ceiling) (optional)  
 
Page 57  
Digital Display Wall Clock Guide  
Specifications  
Appendix G - Warranty  
Limited One-Year Limited Warranty  
Lathem warrants the hardware products described in this guide against defects in material and workmanship for a period of  
one year from date of original purchase from Lathem or from an authorized Lathem reseller. The conditions of this warranty  
and the extent of the responsibility of Lathem Time Corporation (“Lathem”) under this warranty are listed below.  
1. This warranty will become void when service performed by anyone other than an approved Lathem warranty  
service dealer results in damage to the product.  
2. This warranty does not apply to any product which has been subject to abuse, neglect, or accident, or which has  
had the serial number altered or removed, or which has been connected, installed, adjusted, or repaired other  
than in accordance with instructions furnished by Lathem.  
3. This warranty does not cover dealer labor cost for removing and reinstalling the machine for repair, or any  
expendable parts that are readily replaced due to normal use.  
4. The sole responsibility of Lathem under this warranty shall be limited to repair of this product, or replacement  
thereof, at the sole discretion of Lathem.  
5. If it becomes necessary to send the product or any defective part to Lathem or any authorized service dealer, the  
product must be shipped in its original carton or equivalent, fully insured with shipping charges prepaid.  
Lathem will not assume any responsibility for any loss or damage incurred in shipping.  
6. WARRANTY DISCLAIMER AND LIMITATION OF LIABILITY: Except only the limited express warranty  
set forth above, the products are sold with no expressed or implied warranties of any kind, and the implied  
warranties of merchantability and fitness for a particular purpose are hereby expressly disclaimed. No  
warranties are given with respect to products purchased other than from Lathem or an authorized Lathem  
reseller and any such products are purchased "as is, with all faults." In no event will Lathem be liable for any  
direct, indirect, special, incidental or consequential damages arising out of or in connection with the delivery,  
use or inability to use, or performance of this product. In the event any limited remedy given herein shall be  
deemed to have failed of its essential purpose, Lathem's maximum liability shall be to refund the purchase price  
upon return of the product.  
7. Proof of date of purchase from Lathem or an authorized Lathem reseller is required for warranty service on this  
product.  
8. This Warranty grants specific legal rights. Additional legal rights, which may vary by locale, may also apply.  
9. Should any difficulties arise with the performance of this product during warranty, or with any Lathem  
authorized service centers, contact Lathem Time at the address below.  
Lathem Time  
200 Selig Drive, SW, Atlanta, GA 30336  
404-691-0405  
Copyright © 2003 Lathem Time Corporation. All rights reserved.  
 

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