Table of Contents:

Definition and Overview

1. Introduction

2. Why Fax Testing Is Necessary

3. Fax Operation Overview

4. Basic Fax System Structure and Process

5. Message Repetitions and Time-Outs

6. Fax System Test Issues

7. Network Test Issues

8. Common Deviations from ITU Standards

9. Fax Testing Customer Types

10. Fax Testing Application Areas

11. Conclusion

Self-Test

Glossary

PDF of this tutorial

BPS
bits per second

CED
responding unit answer tone

CFR
confirmation to receive

CNG
calling unit announce tone

DCN
disconnect

DCS
digital command signal

DIS
digital identification signal

DTC
digital transmit command

DTMF
dual-tone multifrequency

DTS
digital transmit command

ECM
error connection mode

EOM
multipage signal

EOP
end of procedure

FoIP
fax over IP

FSK
frequency shift keying

FTT
failure to train

HDLC
high-level data link control

IP
Internet protocol

ITU
International Telecommunications Union

LAN
local-area network

MCF
message confirmation

MPS
multipage signal

QoS
quality of service

RNR
receiver not ready

RR
receiver ready

RTN
retrain negative

RTP
retrain positive

T.30
defines procedures and message sequences used for fax communications

T.37
IP–fax protocol for the store-and-forward transmission of FoIP networks

T.38
IP–fax protocol for the real-time transmission of FoIP networks

T.4
defines algorithms used for one-dimensional and two-dimensional data compression

T.6
defines algorithms used for image compression for error correction mode

TCF
training check function

V.17, V.29, V.27 ter
defines modulation used for transmission of image data

V.21
defines modulation used for transmission of control messages in conventional fax

V.34 fax
defines modulation and procedures used for transmission of image and control data

VoIP
voice over IP

WAN
wide-area network