I have VWIC2-2FXS. 1st port is connected to Brother fax machine. 2nd port is empty. When the fax goes off hook and dials to PSTN, the 2nd port is also up and the fax machine gets 2 tones, the first tone is connecting tone and the second tone is busy tone which I believe comes from the 2nd port.
But, if the 1st port is connected to my laptop and using soft-fax from windows, it works fine.
How to investigate this kind of issue ?
dial-peer voice 1 pots
description PSTN local calls
dial-peer voice 3 pots
description *** Fax ***
there is no dial-peer pointing to port 0/3/1 (2nd port), and there is no device connected to the 2nd port as well.
any suggestion would be appreciated.
You probably have too many wires / pins connected in the cable from the FAX machine.
Make sure pins 2 & 5 do not have anything connected.