VoIP Network Requirements for Color Faxes

Color faxes are always sent and received with ECM (Error Correction Mode) enabled. Practice shows that some VoIP providers for some reason do not provide support for Error Correction Mode and this does not depend on the Fax Voip T.38 Modem or your fax software settings. Note that sending and receiving of color faxes is not possible in this case.

At the same time, errors within the data being transmitted are not allowed. Experiments show that when using VoIP providers with poor quality of the termination, transfer of a color fax usually fails. Nevertheless transfer of black and white faxes can be quite successful in the cases described. This notification is especially true for color faxes transmitted in audio mode (fax over G.711 codec).

Thus, the requirements for VoIP network to send and receive color faxes can be formulated as follows:

• ECM (Error Correction Mode) for faxes should be enabled in your VoIP network.
• The quality of VoIP termination should be good enough.