I have a 2811 router with 1 primary rate and 1 fxs interface. On the fxs interface i have a fax machine. The fax call comes in over the pri and is sent to the fxs interface. Unfortunately there are a lot of failures with the inbound faxes. Even from the same numbers. About 4/10 fail.
Now when running the debug isdn q931 and voip ccapi the only thing i can see is that vad is on for the inbound fax call and as the fax is on a pots interface can this make a difference? Can i rectify by adding a generic voip interface with no vad even though this is an inbound fax and inbound dial-peer is 1 and outbound is 2?