Chapter 7: Service and troubleshooting 
P/N 3101890-EN • REV 006 • ISS 21JUN18  131 
VM-DACT Dual Line Dialer Card troubleshooting 
LED indicator diagnostics 
LINE 1 and LINE 2 LEDs on the VM-DACT provide diagnostic information. See the tables below for a description 
of the LEDs and their dialing and data transmission states. 
Figure 43: VM-DACT LED indicators 
 
 
  Description    Label   
1  Indicates line 1 telephone activity    RX  Indicates receive activity 
2  Indicates line 2 telephone activity    TX  Indicates transmit activity 
 
Table 48: VM-DACT LINE 1 and LINE 2 LED states 
 state  LINE 1 description  LINE 2 description 
  There is no activity  There is no activity 
  LINE 1 has been seized  LINE 2 has been seized 
  Dialer or modem data is being passed 
on LINE 1 
Dialer data is being passed on Line 2 
(modem data is passed only on LINE 1) 
LEDs)  The application code or configuration code is downloading from the CPU or VM-CU 
  Reflects ringing on LINE 1 (flashing 
pattern detected) 
N/A (LINE 2 does not have ring detection) 
Cellular capture module problems 
To troubleshoot problems with a cellular capture module, refer to the installation manual received with the 
module. 
Audible diagnostics 
Obtain an audio amplifier device locally for listening to the distinctive sounds associated with dialing, receiving 
handshakes, transmitting data, and receiving acknowledgements. Place a 0.1 μF, 200 V or greater capacitor in 
series with one of the leads. Alternately, you can use a lineman’s handset in monitor mode. 
During downloading from a remote computer, you will hear the distinct sound of modems establishing a 
connection, and then a series of rapid chirps as data is transmitted. 
LINE 
1
LINE 
2
RX TX
LINE 1
LINE 2
RX
TX