Lathem LTR4-512 User Manual

LTRx-512 User’s Guide 

 
Thank you for purchasing your new MASTER CLOCK. You can use your new Master to 
ring bells or turn on circuits for up to 99 seconds, as well as to synchronize the time on 
secondary wall clocks or devices. This manual covers 3 models of MASTER clocks: the 
LTR4-512, the LTR8-512 and the LTR8-512M 
 

 

System Clock 
Correction 

1 correction type running, 
plus RS485 correction 

Up to 2 like or dissimilar 
correction types running 
simultaneously, plus RS485 
correction 

Up to 2 like or dissimilar 
correction types running 
simultaneously, plus RS485 
correction 

Bell Circuits 

4 with no clock correction 
2 with 1 clock correction 

8 with no clock correction 
6 with 1 clock correction 
4 with 2 clock correction  

8 with no clock correction 
6 with 1 clock correction 
4 with 2 clock correction  

Certifications 

UL, cUL,  
 

UL, cUL,  
FCC, DOC (internal modem) 

UL, cUL,  
FCC, DOC (internal modem) 

PC Interface Software 

None 

RS-232, RS-485 
 

RS-232, RS-485,  
Modem  

Atomic clock 
synchronization 

No 

No 

Yes. Requires the 
MasterLink software 

Remote Schedule 
selector switch 
(optional) 

No Yes  Yes 

 

If your Master has 4 lights on the front panel, then you have the model LTR4-512 

CLK 1

1

2

3

4

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ent er

1

2

3

4

5

6

7

8

9

0

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If your Master has 8 lights at the left of the front panel, then you have the model LTR8-512. If 
the TR light at the keypad is lit, then you have the model LTR8-512M

 

SD

TR

RD

CD

CLK 2

CLK 1

1

2

3

4

5

6

7

8

cancel

ent er

1

2

3

4

5

6

7

8

9

0

*

#

 

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