atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Channel Bank problems

I have a question about the T1 Channel Bank. We have TDS Telecom installed a channel bank with FXS card, and connect those analog lines to key system, and fax modem. All the voice lines are perfect, but the faxes are not working properly. The fax line bypasses the key system, and connect directly to the fax card, and then to a server. Many faxes are failing everyday. Any suggestions?

I would not suspect the channel bank if the other voice lines work. Try a standard phone on the fax line and check the voice quality. Then, try a laptop with a modem and see what the fastest dialup speed you can achieve is. have you tried the fax equipment on other phone lines? Roll the fax's FXS cards with another and check for a difference. Troubleshoot and test not guess.

which fax's are failing?, incoming, outgoing or both.

Have them check the circuit also.
You may find if all faxes are failing and voice seems to be good. You may be getting slips on the circuit.

You may be able to hear it if you stay on the line and hold a conversation. sometimes it sounds like you missed the first or last part of a word or you might here a little squeal.

Good point BIGDOG3c!
Connect a PC with dialup on any of those lines and if you get knocked off after a short time you have slips.

Thank you so much for all the valuable input. TDS Metrocom has found some interesting information about this problem. When our fax modem goes off the hook and dial the phone number, the fax modem is dialing the entire phone number in one second. The time frame between each DTMF tone is 80 ms. So, the switch is not registering the entire dialed digits. They have a EWSD switch, and since the switch is not catching all the dialed digits, our faxes are failing. Any suggestion?

You might check to see if there is an Extended dtmf setting on the fax usually this is 160ms.