Service and troubleshooting 
EST3 Installation and Service Manual  8.49 
Device troubleshooting 
Each Signature series device has a red and green LED. Their 
functions are indicated in Table 8-31. These LEDs are useful 
when trying to determine the communication and alarm or active 
status of Signature devices. 
 
Table 8-31: Signature device LEDs 
LED Device status 
Green flashing  Normal communication 
Red flashing  Alarm or Active 
(either input of dual input modules) 
Red and Green 
steady 
Stand-alone Alarm or Active 
(either input of dual input modules) 
 
Table 8-32 lists common troubles and possible causes for 
Signature Series modules. For detailed information on 
identifying and locating Signature device problems, refer to the 
Signature Diagnostic Tools Section found later in this chapter. 
 
Table 8-32: Signature module troubleshooting matrix 
Module not responding correctly 
C 
C 
1 
C 
C 
2 
C 
R 
C 
R 
R 
C 
T 
1 
C
T 
2 
M
M
1 
U
M 
W
T 
M 
Possible Causes 
x  x x x x x x x x Module installed in wrong location or 
improperly addressed 
x  x x x x x x x x Module not entered into Signature database 
x  x      x  x    x    Incorrect personality code loaded into 
module 
          x    x    Personality code for unused portion of 
module not set at 0 (P-codes 1, 2, 3, 4, 8, 13, 
14, 16, and 18) 
   x  Jumper JP1 set incorrectly (P-code 8) 
              x    24 Vdc for smoke power low or missing 
(P-codes 3, 14, 18, 20, and 21) 
          x    x  x  Inputs 1 and 2 swapped (P-codes 1, 2, 3, 
and 4) 
 x  Signal sources 1 and 2 swapped (P-code 7) 
x  x  x    x  x  x  x  x  Ground Fault on data circuit or (-) side of 
input / output circuit 
Module in trouble on Signature controller module