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CTM
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CTM (Cellular Text Telephone Modem) is a text based communications protocol to offer support to
hearing and speech impaired people. Hearing or speech impaired persons can communicate using a
teletype (TTY) terminal connected to the mobile phone via a CTM Modem. The TTY signals are sent
alongside speech so it is possible to configure the system to enable speaking and hearing as well as
typing or receiving text to the TTY device. See below for the options available:
CTM Mode
Description
Full
Text entered on the terminal is sent to the other party. Received text from the
other party is displayed on the terminal.
Talk & Read
Received text is displayed on the terminal, Voice is relayed to the other party.
Write & Hear
Text entered on the terminal is sent to the other party with incoming speech heard
from the other party.
Off
All CTM is disabled, use the phone as normal.
If you are using a TTY device make sure the terminal baud rate is set to 45.45 bps
If you are using a terminal with a CTM modem built in then select CTM Off on the
handset.