I have recently installed two UC320 systems for customers, each trying to use the built-in FXS port as an office extension. Each system is running firmware 2.1.2, and each system is working fine with the exception of the telephone connected to the FXS port. Here are the specific problems:
System 1: 16 SPA509G telephones plus one plain old telephone connected to the FXS port. The SPA phones can call internally to each other and externally fine through 4 POTS lines. If any SPA phone dials the FXS internal extension (33), they are immediately forwarded to a message that says "The person at extension 33 is unavailable. Please leave a message." The voicemail for this extension has not been set up yet, resulting in this canned message. The extension never rings. The user on extension 33 can place a call to any internal extension or external number without issues. When another internal extension is dialed, the caller ID at one of the SPA phones shows "unavailable" as the calling number. We've tried re-assigning extension numbers for the FXS port, switched to a different basic telephone, restarted the system, etc. without success. Any ideas?
System 2: 4 SPA525G2 telephones plus one plain old telephone connected to the FXS port. The SPA phones can call internally to each other and externally fine through a SIP trunk. If any SPA phone dials the FXS extension (104), the extension rings and works fine, including internal caller ID showing the internal calling extension number. If the user on extension 104 attempts to call any other internal extension, they immediately get a fast busy signal and the other extension never rings. If the user on extension 104 calls an external number via "9" through the SIP trunk, all works as expected. As above, we've tested different basic telephones on the FXS port, restarted the sytem, etc. without success. Because this system has been installed for several months now, we know that this FXS port and phone was working normally on an earlier firmware release. Any ideas?