Zhone Technologies IMACS-200 - Manual (Page 159)

FXS Ports 6-11
6.4 FXS Error Messages
Refer to Appendix B in the System Reference Guide for further information on Error
Messages regarding this port.
6.5 FXS port Troubleshooting
The FXS port may be faulty if a voice signal is not received at one end of a circuit, or if
signaling is not detected. The following are possible causes:
• Faulty receiving CPE at the near end (where the problem was first noticed)
• Faulty transmitting CPE at the far (opposite) end
• Faulty cabling between the CPE and FXS port at the near end
• Faulty cabling between the CPE and FXS or FXO port at the far end
• T1 network failure
• Improper port configuration at either end (e.g., time slot and/or WAN port assignments)
First, verify that the T1 network has not failed. Check for a CGA-Red alarm on the associated
WAN port at the end where the incoming VF signal loss is first noticed. The CGA indicates
that the incoming network signal was lost (or that the receiving WAN port is out of frame).
During the CGA, all voice ports with time slots on that WAN port will also be disabled, and
the associated far-end WAN port will be in a CGA-Yellow alarm state. If the network is faulty,
you must clear that trouble to restore your circuits.
If the network is okay, verify that the proper WAN ports and time slots are assigned to the
associated FXS and FXO voice ports at both ends, as previously outlined in this chapter. In a
point-to-point network, the near-end and far-end FX port ports should both be assigned the
same WAN port and time slot number. Also make sure the other parameters (such as the
transmit and receive TLPs) are set properly at both ends.
If the FX port parameters are correct at both ends, and if the network is okay, the trouble is
isolated to the FXS port or the associated port. Proceed as follows:
1. At the far end, activate an analog loopback on the FX port.
2. Send a 0 dBm (digital milliwatt) test signal toward the CPE at that end. That signal will
be substituted for the normal signal coming from the far-end CPE; it will be sent back to
the CPE at your end via the loopback path.
3. Check your CPE for this signal. If it is present, the far-end CPE or cabling to the far-end
FX port is probably faulty. Disable the loopback and test signal there, and fix the problem.
If you still don’t receive a signal, go to step 4.