When implementing a Fax over IP (FoIP) solution for your business, there are two main options that you can choose between: T.38 and G.711. Today we are going to focus on the differences, and the pros and cons, of T.38 and G.711 for enterprise fax solutions.
T.38 versus G.711
A T.38 fax is an ITU-T recommendation that allows fax data to be carried over IP networks. When you send a fax over an IP network, the data is directly transmitted in T.38 without any conversion to an audio stream.
Some of the benefits of using T.38 include:
- A significant reduction in the required bandwidth
- Support for data and control of redundancy, which mitigates the effects of packet loss. Packet loss results large gaps in fax data and is prevented by switching to a lower transmission speed.
Some of the disadvantages of using T.38 include:
- Gateway support for fax parameters (V.34 transmission speeds, Error Correction Mode, etc.) is not universal.
- Can add latency and cost to fax services.
G.711 is an ITU-T recommendation for Pulse Code Modulation (PCM) of voice frequencies. G.711 requires high bandwidth (about 64 kbps) because it uses an uncompressed format. When sending a fax using G.711, digital fax data converted to a PCM audio stream, which is then sent as G.711 Real-time Transport Protocol (RTP) packets.
Some of the benefits of using G.711 include:
- A simpler and often more cost-effective approach than T.38 because of its ability to leverage voice data infrastructure.
- Less likely to suffer interoperability issues with different vendors’ products.
Some of the disadvantages of using G.711 include:
- Not optimized for fax transport over IP networks.
- Does not typically support packet redundancy.
- Can result in significant packet loss when used to transmit moden data.
- Increased transmission errors are likely.
Please make sure to consult with your Fax Guys account manager prior to changing your settings as significant transmission errors can reduce the reliability of your fax server.
Get More Information Immediately
There is a lot to cover when it comes to T.38 and G.711, including their performance against IP network impairments and the impact of the frequency of these impairments. To learn everything you need to know about T.38 and G.711, download our free white paper at RightFax University. If you have any questions as to which solution is right for your organization, don’t hesitate to get in touch with our team.
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