Have just tested this service by faxing to myself.
It offers two ways of sending a fax:
via e-mail or
via an online web form.
The web form worked and I received the fax within 2 - 3 minutes.
But the e-mail method failed twice with an error message:
Quote:message text rejected by finch-tpc-1.fax.demon.net:
550 We don't support attachments of that type
Then it dawned on me that the e-mail message has to be sent in
plain text mode (not HTML).
That way it works!