Dialogic 6.2 Manuale Utente

Processing Media Using the T.38 Protocol

November 2009

238

The Brooktrout SDK supports real-time sending and receiving faxes 

over IP following the T.38 protocol for exchanging messages and 

data through IP fax gateways or IAF devices over an IP network. 

Because Brooktrout’s Bfv Call Control API uniformly supports a 

wide set of transports including IP, you can use the same fax 

functions for fax over IP as when sending faxes over the PSTN. You 

can configure your system using the Brooktrout Configuration Tool 

(a GUI product) or by editing user-defined files. 

Using standard fax machines over the PSTN, the following 

information is presented.

„

The sender of a fax gets immediate notification of a fax being 

sent successfully.

„

The receiver gets information on the sender’s telephone number 

and the time the fax was received. 

Bfv’s IP fax support provides this information as well.

Traditionally, faxing has been done over the TDM telephone 

network, as defined in the ITU specification T.30. In a traditional 

PSTN based T.30-only fax transmission, sending a fax requires three 

fax components:

T.30 Protocol Engine

While T.30 is a mature technology, an effective T.30 implementation 

is complex due in large part to the challenge of connecting with the 

installed base of 120 million fax machines whose own compliance to 

the standard varies considerably.

Image Conversion Engine

The sending device must adapt (scale and transcode) the image to 

the capabilities of the receiver. The receiver must check the received 

file for errors and try to correct ones that occur.

Modem 

This is the vehicle to carry the protocol and image data across the 

PSTN network.