I'm trying to get my internal conexant fax modem to work with my digital phone service with vonage. Every time I try to fax, the fax program says the call is busy which is not the case - I manually dialed the phone # to test.

Vonage says to lower a fax modem to 9600 baud. I did this.
It also says to turn OFF ECM.

How do i do this with a faxmodem?

Maybe you have to wait for a dial tone before you can start dialling a number?
In some phone systems you don't get a dial tone but you still have to wait a couple of seconds before you can start punching in numbers.

You can tell your modem to wait for a dial tone in settings. You an add a pause in the number you are dialling by inserting a comma.

I don't think that is the issue, but I will try it.

I'm still trying to figure out ECM.

ECM is a fax error correction thingy. I think you can toggle it in the fax software if at all.

Anyone know the command for turning off ECM in a conexant fax modem?