[asterisk-users] Modem calls

[Time Bandit]

>  I need to pass modem calls through a TDM400 card. Conecting the modem to
> the FXS port (ZAP/1), it should be put through the FXO port (ZAP/4)
> directly.
According to Digium, Fax calls (and modem calls) are not supported on
the TDM400 or TDM2400. They are designed for voice only. If you get it
to work, you're lucky.

Sangoma test all their cards with faxes, so maybe you should try their card.

For your problem, run zttest and adjust everything to try to obtain
100%, this may make it work.

hth