T 38 Compatible Fax Machine

Make sure when connecting a fax machine to your spa that you select reinvite next to fax passthru method.

T 38 compatible fax machine.

Once we get the 200 ok from flowroute it s all t 38 media both ways. We have compiled an extensive list of platforms and how to configure those devices to perform t 38 fax over ip foip. Fax machine ip fax compatible machine ip fax compatible machine ip fax compatible machine sip server intranet branch o ce c branch o ce a branch o ce b ip network note the ip fax of this product is compliant with recommendation t 38 procedures for real time group 3 facsimile communication over ip networks. The t 38 recommendation defines the use of both tcp and udp to transport t 38 packets.

All platforms on this page have been rigorously tested and certified as compatible with our service by our t 38 fax interoperability team. Implementations tend to use udp due to tcp s. In essence a t38 compatible service converts a fax to an image and then sends it to another t38 compatible fax device which converts the image back to an analog fax signal that can be fed into a standard fax machine. If both sides of the call support t 38 the call will still start as an analog call and in theory will switch to t 38 when the call is then detected as being a fax.

As a result these machines can more reliably receive faxes sent over voip. This is then sent either to a t 38 enabled end point such as fax machine or fax server or another t 38 gateway that converts it back to pstn pcm or analog signal and terminates the fax on a t 30 device. The gateway works by taking your fax machine s signal and converting it into an internet compatible one rather than first digitizing it into an audio signal. Dcs our fax machine communicates the capabilities and starts training.

For the g3 fax machine on an analog line this process will be transparent. T 38 is described in rfc 3362 and defines how a device should communicate the fax data. Since the vast majority of fax machines in existence today do not have t 38 built in any fax machine starts off the call as a regular analog call. A configuration guide is included for each device we certify as t 38 fax compatible.

In the diagram above both the gateway and the fax machine behind the gateway would have to be t 38 capable. The analog fax machine does not need to know t 38. Now the flow gets interesting more fax ey. Make sure you select the proper codec need it for your fax transmission which only g 711u or g 711a are the only option that can be used when selecting the fax passthru codec.

Fortunately most newer fax machines utilize a newer t 38 protocol.