Telephony
Telephony: what the shift to IP changes
Fax is only one use of the telephone network. When that network changes nature, the use changes with it — here are the files explaining the transition under way.
Current file
Understanding the network
The protocols carrying a fax transmission belong as much to telephony as to fax itself. These pages explain them.
T.38: why analogue fax fails over IP, and what repairs it
Why an analogue fax machine fails on a voice-over-IP line, and how T.38 restores reliable delivery by carrying the protocol rather than the sound.
T.30: the conversation two fax machines hold before exchanging anything
The standard behind every exchange between two fax machines: how they identify each other, agree on a speed, and confirm each page received.