gchiu:sbiddle: There should be no issues using this with VFX.
I tried registering with VFX but it wouldn't register, and that's why I next tried it with asterisk.
I used username = fromuser, password = secret, and authentication name = username
Maybe I should try a different combination.
If you're trying to send via Asterisk you clearly need to understand how faxing works in Asterisk. If you simply registered as an extension and tried to send a T.38 fax then out of the box it will fail.
Yep, that's what I tried. I have T.38 passthrough, and extension set to detect fax to stop echo cancellation.
You don't want Asterisk to touch the fax. I assume you've got reinvites configured correctly? I haven't used this software as an Asterisk extension, but different T.38 endpoints do different things and need to be configured differently. At the end of the day a re-invite has to occur for the T.38 to be negotiated so some experimentation may be required.