TTY Support

Discussion in '3CX Phone System - General' started by ndraves, Jul 31, 2007.

  1. ndraves

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    Does anyone know if the auto-attendent supports callers who call with TTYs?
     
  2. Anonymous

    Anonymous Guest

    Do not think it does, having said that how is the DTMF handled?

    I never head any dealing with devices like this, but i believe they rely on DTMF is it not? So they can use the selections but how the voice is translated to text I do not know.

    Do yo uhave some more info on how this works on PSTN type traffic?
     
  3. ndraves

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    I believe TTYs use a system more closely related to a modem than DTMF.

    TTYs don't do any voice translation. Most TTY users call a relay service that will basically read what the TTY user types and voice it to the other party and then types what the voice party says.
     
  4. Anonymous

    Anonymous Guest

    From http://en.wikipedia.org/wiki/Telecommunications_devices_for_the_deaf#Protocols
    There are many different textphone standards. The original standard used by TDDs is the Baudot code implemented asynchronously at either 45.5 or 50 baud, 1 start bit, 5 data bits, and 1.5 stop bits. Baudot is a common protocol in the US. In Europe, different states use different protocols. For example, V.21 is found in the UK and several Scandinavian countries. Other protocols used for text telephony are EDT, DTMF, V.23, etc.

    The TDD/TTY protocols are generally incompatible with standard Hayes-compatible modems. In 1994 the ITU approved the V.18 standard. V.18 is a dual standard. It is both an umbrella protocol that allows recognition and interoperability of some of the most commonly used textphone protocols, as well as offering a native V.18 mode, which is an ASCII full- or half-duplex modulation method.

    Computers can, with appropriate software and modem, emulate a V.18 TDD. Some voice modems, coupled with appropriate software, can now be converted to TDD modems by using a software-based decoder for TDD tones.

    In the UK, a virtual V.18 network, called TextDirect, exists as part of the Public Switched Telephone Network, thereby offering interoperability between textphones using different protocols. The platform also offers additional functionality like call progress and status information in text and automatic invocation of a relay service for speech-to-text calls.

    In addition to regular Baudot, the UltraTec company implements another protocol known as Enhanced TTY, which it calls "Turbo Code," in its products. Turbo Code has some advantages over Baudot protocols, such as a higher data rate, full ASCII compliance, and full-duplex capability. However, Turbo Code is proprietary, and UltraTec only gives its specifications to parties who are willing to license it.


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    If they use straight DTMF and the ATA is able to pass that than you be ok in my opinion. But test it first.

    Otherwise I think you be out of luck.
     

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