Aculab's Group 3 fax software
allows the transmission and reception of faxes within T.30 and T.37 specifications as detailed below. Using Prosody's Group 3 fax, a system can discriminate between incoming fax or voice calls allowing an application to route the call to either fax or speech resources. With Prosody media processing resource software being available to download from software downloads at no extra cost, this solution brings unmatched value per channel.


As the use of fax has proliferated, the demand for open computer telephony (CT) based solutions has grown and the use of proprietary hardware solutions is no longer a fixed expectation. Services like fax-on-demand and fax broadcast have become basic business tools for many organisations in different customer facing and business-to-business industry sectors. This creates many market opportunities for developers and integrators. With the flexibility of a fax option on intelligent media processing resource cards like Prosody, dedicated fax cards become a thing of the past, especially when the benefit of learning and developing with a single, generic API is considered.

Group 3 fax and TiNG architecture

The firmware for Group 3 fax is available to download from software downloads and is incorporated into the TiNG architecture . TiNG allows a developer to choose multiple functions, within the capacities of each Prosody DSP, to create the most cost effective communications solution. Up to four DSPs are available on a single card, benefiting the developer with a wide choice of functional permutations for building real time CT solutions.

With TiNG, and using V.29, for example, a single DSP will support up to 48 simultaneous fax transmission processes and with four DSPs, 192 can be achieved per card. Receiving faxes is more resource intensive and up to 12 simultaneous processes can be achieved per DSP, giving a maximum of 48 per card. Aculab provides a TiNG utility tool to assist in calculating optimum feature mix combinations, including simultaneous fax transmit and receive, per DSP.

The total number of simultaneous fax channels per system is governed by the host PC's processing and memory capability, so channel count will need calculating on a per system basis.


Feature summary
Aculab's Group 3 fax software will provide for the transmission and reception of Group 3 TIFF image files, monitoring of call progress (incoming and outgoing) and call configuration capabilities.

Prosody offers a TIFF image manipulation library, which allows the generation of TIFF images from ASCII text input. An application is able to control the selection and transmission of fax header and individual pages. Control of page length and resolution is also provided and blank, cover or text only pages can be created. A text insertion capability (with support for multiple fonts) enables, for example, page headers and footers to be included. In addition each page can be optionally coded into multiple formats, which means the capabilities of a remote machine can be matched without resorting to on-the-fly image conversion.

On-ramp and off-ramp handling of faxes to and from email, according to the T.37 simple mode specification, is provided as a separate module. This gives the ability to send and receive faxes via email using the SMTP protocol and to receive emails from a server via the POP3 protocol.

Programming interface
Fax features are available as an extension of the Aculab generic API, providing a consistent look and feel when developing with Aculab digital network access or media processing resources . A copy of the generic API for fax is available from technical documents to allow developers a preview opportunity.

Image compression

Images can be received or transmitted in TIFF format using the following compression algorithms according to ITU-T specifications:
MH Modified Huffman data compression (ITU-T T.4 recommendation)

MR Modified Read data compression (ITU-T T.4 recommendation)

MMR Modified Modified Read data compression (ITU-T T.6 recommendation)

Group 3 fax specification conformance

Aculab’s Group 3 fax software conforms to the following ITU-T and IETF specifications:

V.21 300 bits/s for T.30 fax negotiation
V.17 7200, 9600, 12 000 and 14 400 bits/s fax transmit only
V.27ter 2400, 4800 bits/s
V.29 7200, 9600 bits/s
ECM (Error correction mode) transmission and reception supported
RFC2306 Group 3 TIFF.


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