said by jgwilliams:
Faxing over VoIP is not reliable, you will find yourself resending a good percentage of your faxes. Additionally fax documents are sent by way of g711, so each line would take about 100k...
This is not entirely true - we fax daily over VOIP on our Quintum H.323 network and have NEVER had to resend. If your statement is related to Faxing via Vonage, P8, Voicepulse (or anyone else I may have missed), please qualify your statement.