EST EST3X - 3-LDSM Display Support Module Troubleshooting; 3-MODCOM Modem Communicator Module Troubleshooting

Chapter 7: Service and troubleshooting
180 EST3X Technical Reference Manual
Problem
Possible cause
The
IDC circuit is not working • There is an incompatible two-wire smoke detectors
• There is excessive wiring resistance or capacitance
• There is an open circuit on the line
3-LDSM Display Support module troubleshooting
Table 47: 3-LDSM Display Support module troubleshooting
Problem
Possible cause
All control
-display module
LED
s and buttons are
inoperative
but the 3-LDSM is
working correctly
• The ribbon cable between the control-display module and
3-LDSM is loose or defective
• The 3-LDSM module is not defined in the 3-SDU
• The control-display not defined in the 3-SDU
• The control-display is defective
3-MODCOM Modem Communicator module
troubleshooting
LED indicator diagnostics
LINE 1 and LINE 2 LEDs on the 3-MODCOM provide diagnostic information. See
the tables below for a description of the LEDs and their dialing and data
transmission states.
Figure 46: 3-MODCOM LED indicators
LINE
1
LINE
2
RX TX
LINE 1
LINE 2
RX
TX
Label
Description Label Description
LINE
1 Indicates line 1 telephone activity RX Indicates receive activity
LINE
2 Indicates line 2 telephone activity TX Indicates transmit activity