Vonage and faxmodem cards - need help

[Tedster]

I have Vonage VoIP with a linksys router. I am also using a Conexant modem just for a fax. Trouble is, everytime I try to fax something, the fax says the phone is busy no matter what number I dial. It's ridiculous. I have lowered the bps on the fax to 9600 like Vonage says, however I don't know how to turn off ECM. That is the other thing Vonage says to do.

any suggestions?