Overview

A fax (short for facsimile), is the transmission of  scanned printed material (text or images) via voice grade telephone lines.  High speed rates as high as 33.4 kbps (V.34 or Super Group 3) can be achieved over conventional telephone lines. When combined with compression schemes, many pages of print can be transmitted in minutes.  When transmitted over regular telephone lines, a simple protocol called T.30 is used by both fax machines to negotiate transmission parameters and provide reliable transfer of scanned documents. Recently fax transmission is also possible over voice circuits that are packet based.  This form of transmission usually demodulates the modulated signal back to the original scanned bits and then transmits them via packets to the distant end where they are remodulated to be sent to the destination fax machine.

GL has recently introduced single and bulk (100's) call Fax Simulator. This software is capable of transmitting and receiving over many T1 E1 timeslots or through two-wire FXO and FXS lines. The software can emulate many "virtual fax machines" – both transmitter as well as receiver.

The application supports fax over v27, v29, v17 and v34 ITU-T modems. The simulator can transmit multiple pages of fax image, as of now up to 1300 pages can be sent per fax call. Detailed information of the fax call can be obtained during the call. Upon call termination, a summary of the call is provided which contains details about the call status.

Fax Simulator can be used with any GL Protocol Emulation tools such as MAPS™ CAS emulator, MAPS™ ISDN emulator, and MAPS™ SS7 emulator to simulate complete real time Fax calls.

GL also supports FaxScan™ (fax decoder/demodulator) software that processes 2-Wire or 4-Wire captures and analyzes voiceband traffic files for fax traffic. The application operates either stand-alone from a batch file or as part of the GL's VoiceBand Analysis application to produce decoded fax image TIFF files and other transmission information.

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Fax Emulation Applications

Typical applications of our Fax Emulation software are load testing of fax servers, qualification testing of T.38 Gateways, testing of ATAs (Analog Terminal Adapters), testing of fax machines, and many more. 

Features and applications are:

• Load Testing - sending or receiving up to hundreds of faxes simultaneously; one end can send and receive simultaneously on different timeslots; over many T1 E1 lines; over many FXO or FXS lines; any signaling protocol can be used such as PRI ISDN, SS7, or CAS
• V.34 Testing - there are many fax modulations and V.34 is the fastest, permitting many pages to be transmitted quickly.
• High Speed / Low Speed - fax protocol consists of low speed handshaking and high speed image transmission
• Multiple Pages - single or multiple page fax transmission is supported
• With or without ECM - Error Correction Mode permits the retransmission of erred pages.
• Alaw and µlaw - In TDM networks, USA uses µlaw and the rest of the world use Alaw – both coding standards are supported
• Over T1/E1, PSTN, IP - Fax transmission may be over T1 E1 digital lines, over PSTN FXO / FXS lines, or over VoIP (packet) networks
• Output Tiff Image

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Supported Platforms

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Fax and Modem Standards

Standard	Description
V.17	Provision for half duplex operation at data signaling rates of: 14400 bps synchronous 12000 bps synchronous 9600 bps synchronous 7200 bps synchronous Quadrature amplitude modulation with synchronous line transmission at 2400 symbols per second Inclusion of data scramblers, adaptive equalizers and eight-state trellis coding Two sequences for training and synchronization: long train & resync
V.27	Use of data signaling rate of 4800 bits per second with 8-phase differentially encoded modulation as described in Recommendation V.27. Reduced rate capability at 2400 bits per second with 4-phase differentially encoded modulation as described in Recommendation V.26.
V.29	Fallback rates of 7200 and 4800 bits per second Combined amplitude and phase modulation with synchronous mode of operation Inclusion of an automatic adaptive equalizer
V.34	half-duplex modes of operation are used for fax Quadrature Amplitude Modulation (QAM) for each channel with synchronous line transmission at selectable symbol rates including the mandatory rates of 2400, 3000, and 3200 symbols/s and the optional rates of 2743, 2800 and 3429 symbols/s Trellis coding for all data signaling rates Adaptive techniques that enable the modem to achieve close to the maximum data signaling rate the channel can support on each connection Exchange of rate sequences during start-up to establish the data signaling rate

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Transmit Fax Session

inform task 1 "TXFAX #1:1 TIFF_FILE 'C:\Tiff File\transmit.tif' CODEC_TYPE ALAW MIN_RATE_TYPE 2400 MAX_RATE_TYPE 4800 ECMENABLED 1 RECORD_PCM TRUE ";

The above command transmits a tiff file named 'transmit.tif' over timeslot 1 of port #1, the data encoding is Alaw and the min data rate is 2400 bps, max data rate is set to 4800 bps, with Error Correction Mode (ECM) and record PCM option enabled.

Multiple instances of fax calls can be generated simultaneously by repeating the above command on different port and timeslot pair.

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Receive Fax Session

inform task 1 "RXFAX #2:1 TIFF_FILE 'C:\Tiff File\receive.tif' CODEC_TYPE ALAW MIN_RATE_TYPE 2400 MAX_RATE_TYPE 4800 ECMENABLED 1 RECORD_PCM TRUE";

The above command receives a fax on E1 Port 2 timeslot 1, and saves the tiff image as 'receive.tif' file with Alaw codec, modem V.27, min data rate 2400 bps, A4 page-size, resolution type 200x200 with ECM and record PCM option enabled to record the signals being exchanged during the FAX reception to a PCM file.

Multiple instances of fax calls can be generated simultaneously by repeating the above command on different port and timeslot pair.

Examples

run task "FaxSimulatorE1:StartFaxSim"; 
inform task 1 "START"; 
inform task 1 "TXFAX #1:1 TIFF_FILE 'C:\Tiff File\transmit.tif' CODEC_TYPE ALAW MIN_RATE_TYPE 2400 MAX_RATE_TYPE 4800 ECMENABLED 1";
inform task 1 "RXFAX #2:1 TIFF_FILE 'C:\Tiff File\receive.tif' CODEC_TYPE ALAW MIN_RATE_TYPE 2400 MAX_RATE_TYPE 4800 ECMENABLED 1";
inform task 1 "STOPFAX #1:1";
inform task 1 "STOPFAX #2:1";
end task*;

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Typical Fax Session

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Test Scenarios for Fax Simulator

Fax Simulator Between tProbe™ and FAX Machine (Over T1/E1)

Sample Script :

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Fax Simulation over T1/E1 to Analog Interface on Dual UTA HD (via Channel Bank)

Sample Script:

inform task * "TXFAX  #1:1 TIFF_FILE 'WinClientServer\FAXSimulator\send\1.tif' CODEC_TYPE ALAW MIN_DATA_RATE 7200 MAX_DATA_RATE 9600 ECMENABLED 1";

Analysis of PCM Files in GL Insight for V.29 Modem

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Fax Simulation over tProbe™ FXO

Sample Scripts

Sending Fax from tProbe™ FXO Port to Fax Machine 

run task "FaxSimulatorE1:StartFaxSim";

inform task * "START";

inform task * "TXFAX #2:1 TIFF_FILE 'WinClientServer\FAX Simulator\send\4.tif' CODEC_TYPE ALAW MIN_RATE_TYPE 2400 MAX_RATE_TYPE 4800 ECMENABLED 1";
This command will transmit 4.tif file on the port 2 timeslot 1 with the  minimum and maximum data rate set to 2400 and 4800

Sending Fax from Fax Machine to tProbe™ FXO  

run task "FaxSimulatorE1:StartFaxSim";

inform task * "START";

inform task * "RXFAX #2:1 TIFF_FILE 'WinClientServer\FAX Simulator\Recv\RCV.tif' CODEC_TYPE ALAW MIN_RATE_TYPE 2400 MAX_RATE_TYPE 4800 ECMENABLED 1";

This command will Receive the fax signal on port 2 timeslot 1 and save the image as  RCV.tif.

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Resources

Please Note: The XX in the Item No. refers to the hardware platform, listed at the bottom of the Buyer's Guide, which the software will be running on. Therefore, XX can either be ETA or EEA (Octal/Quad Boards), PTA or PEA (tProbe Units),UTA or UEA (USB Units), HUT or HUE (Universal Cards), and HDT or HDE (HD cards) depending upon the hardware.

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