I'm trying to get an old AT&T (Lucent/Avaya) 7400B Plus Data Module working with our Avaya Definity G3 PBX. I only want it to be able to dial my PBX line, I don't care about the data communications. My PDX support people say that they have setup my line for it, but it still won't work.
All the cables to LINE, PHONE, PC, and power supply are setup according to 7400B Plus Data Module User's Guide 555-020-710. All DIP Switches set to OFF (Default). See
When the unit is powered up, it performs the POST as per the manual (turning on all status lights in sequence), and I can communicate with it OK from my PC via the serial port. (i.e. I can send it "AT" commands and it responds). The line is working, since my 8410D (which is connected to the PHONE jack on the 7400B) is working OK. I've checked (and replaced) all the cables.
But the 7400B can not connect to a phone line either in voice (ATDP...) or data (ATDT...) dialing mode. An "ATDT..." command times out with a "NO CARRIER" message and an "ATDP..." command does not dial the voice call.
At all times the POWER/TEST light and the DATA light flash continuously. Which, according to the manual means:
"POWER/TEST and DATA LEDs flash together - The 7400B Plus has lost communications with the PBX. Check that the D8W cord is connected between the LINE connector of the 7400B Plus and a PBX wall jack. Note also that the line from the PBX must be properly administered for the 7400B Plus. POWER/TEST light together with the DATA light, also flashes if there is a DCP line problem."
I had thought that having my line administered for the data module would solve the problem, but it is still not working. Is there anything else I need to do on my end to make the 7400B work?