FoIP Technical Overview
Unlike a traditional fax server implementation, in which it is connected to the phone network (PSTN) through a local PBX, FoIP works via a T.38 protocol that describes how to send a fax over a computer data network. T.38 requires a T.38 capable VoIP gateway as well as a T.38-capable fax device.
A fax server that sends or receives faxes using T.38 looks just like any other non-FoIP fax device to its partner. The two end points establish a session, send and verify the transmission of one or more pages and then complete the session with active confirmations from both sides. The difference with a FoIP enabled server is that the first part of the communication session from the server to the network traverses an IP network rather than traveling directly over the PSTN. If the partner device is directly addressable on the same network, the session can use T.38 for the entire transmission. But if the devices are separated by the telephone line, the IP switch manages the “unwrapping” of T.38 packets into standard T.30 fax transmissions over the PSTN.
To implement the FoIP capabilities of the Cloud FoIP fax server, we use the Dialogic Brooktrout SR140 fax software, available in densities ranging from 2 to 60 channels and supporting up to 120 ports in a single server. Additional channels can be installed with new software license keys.
The Dialogic SR140 FoIP product is compliant to the T.38, SIP and H.323 industry standards and is regularly tested to check compatibility with additional PBX’s, Gateways, SIP Trunking interfaces and other devices.
To verify interoperability with your IP environment, please contact us for an analysis of your IP environment and configuration recommendations.