Specifications

Chapter 4 – Call Control Commands
Multi-Tech Systems, Inc. CDMA AT Commands Reference Guide (PN S000294K) 23
DTMF Signals +VTD, +VTS
+VTD
Description: The product enables the user application to send DTMF tones over the CDMA network. This command is
used to define tone duration (the default value is 0,0). To define this duration, the application uses:
AT+VTD=<on>,<off>.
Values: <on> on tone duration
0 95 milliseconds
1 150 milliseconds
2 200 milliseconds
3 250 milliseconds
4 300 milliseconds
5 350 milliseconds
<off> off tone duration
0 60 milliseconds
1 100 milliseconds
2 150 milliseconds
3 200 milliseconds
Syntax: Command syntax: AT+VTD=<on>,<off>
Command Possible Responses
AT+VTD=4,3
Note: To define 300 ms on tone duration and 200 ms off tone duration.
OK
Note: Command valid
AT+VTD=?
Note: Display valid parameter ranges.
+VTD: (0-5), (0-3)
OK
+VTS
Description: The product supports the ability of the user application to send burst DTMF tones over the CDMA network.
This command enables the transmission of burst DTMF tones. To transmit DTMF tones (only when there is
an active call), the application uses: AT+VTS=<Tone> where <Tone> is in {0-9,*,#}.
Syntax: Command syntax: AT+VTS=<Tone>
Command Possible Responses
AT+VTS=# OK
Note: Command valid
AT+VTS=11 OK
AT+VTS=4 OK
Informative Example: To send tone sequence 13#, the application sends: AT+VTS=13#
DTMF Start and Stop Continuous +WSDT, +WSDS
Description: Starts and stops a continuous DTMF tone while in a call state (conversation).
Values: <X>: (0-9, #,*)
Syntax: Command syntax: AT+WSDT=<X>
Command Possible Responses
AT+WSDT=2 OK
Starts DTMF tone
AT+WSDS OK
Stops DTMF tone