Asterisk has some basic Alpha level code (as of December 2006) with support for TTY.
There is some additional information available at tdd mode. Asterisk svn trunk
has support for T.140 realtime text and improvements on the TDD mode
in zaptel. TDD support is being developed in SIP too as well as a TDD gateway between
zaptel (analog devices) and SIP/T.140 realtime text in RTP.
See Also
- Network World article on VOIP and TTY (2002)
- Wikipedia TTY article
- FACT OR FICTION - TTY WORKS OVER VOICE OVER IP Cisco conference paper in 2004
- TTY & TTD Over VoIP: Dispelling the "Packet Loss" Myth - Cisco
- TDD/TTY - Information at Assistive Technology.
Page Changes
ToIP ?
New Text-over-IP protocol
ToIP is designed to be part of the Voice/Video/Text-over-IP multi-play services that are being developed today. It is aimed at mainstream use with some features included to make it easier to interwork with TTYs text phones that operate on telephone networks.
TTYs were developed for analog telephone networks. ToIP was developed to use all the features of the Internet. /Barry