Cinterion
®
EHS6 AT Command Set
16.10 AT^SNFTTY
EHS6_ATC_V03.001 15/12/3
Confidential / Released
Page 404 of 513
16.10 AT^SNFTTY Signal TTY/CTM Audio Mode Capability
EHS6 offers basic support for equipment using the CTM standard (Cellular Text Telephone Modems). The ben-
efit of CTM is that text characters typed on a TTY device (Text Telephone Type-writer) can be transformed into
special audio burst signals for reliable transmission via the existing speech channels of a cellular phone system.
If CTM mode is activated, the ME will set the necessary bearer capability bit on outgoing (mobile originated) calls
and incoming calls with this bearer capability bit set are accepted. The TE needs to decode the special audio
burst signals.
If CTM mode is disabled, the ME will clear the bearer capability bit on mobile originated calls and incoming calls
with the bearer capability bit set are rejected because the EHS6 expects that CTM coded speech data cannot
be decoded by the TE.
Designed to set the module's speech system into CTM mode, the AT^SNFTTY command allows a CTM device
to be connected to one of the three audio interfaces of EHS6. Traditional TTY devices that do not incorporate
CTM functionality can be connected through an external TTY-to-CTM adapter.
Related documents: Refer to the relevant standards, such as 3GPP TS 26.226 (ETSI TS 126 226) and 3GPP
TS 23.228 (ETSI TS 123 226). 3GPP documentation can be retrieved, for example, from http://www.3gpp.org/
specs/specs.htm. Application Note 22 "Using TTY/CTM equipment" supplies information needed to connect
TTY/CTM equipment to the EHS6.
Requirements for using TTY/CTM features:
• TTY/CTM functionality requires audio mode 10 which is set by AT^SNFS command.
• Depending on which audio interface the CTM device is connected to, select the appropriate settings via
AT^SAIC.
Syntax
Parameter Description
0
(D)
Audio path is in normal speech mode.
1 Audio path is in TTY/CTM mode.
Test Command
AT^SNFTTY=?
Response(s)
^SNFTTY: (list of supported <audioState>s)
OK
Read Command
AT^SNFTTY?
Response(s)
^SNFTTY: <audioState>
OK
ERROR
+CME ERROR: <err>
Write Command
AT^SNFTTY=<audioState>
Response(s)
OK
ERROR
+CME ERROR: <err>
PIN Last
- - -
<audioState>
(num)(NV)
To Next Page
Loading...
Need help?
General
