Specifications

SIM900 AT Command Manual
SIM900_AT Command Manual_V1.03 82 12/24/2010
OK
Parameters
See Write Command
Write Command
Generate tone
Duration is set by
+VTD
AT+VTS=<dtmf-
string>
Response
This Command allows the transmission of DTMF tones and arbitrary
tones in voice mode. These tones may be used (for example) when
announcing the start of a recording period.
Note: D is used only for dialing.
OK
If error is related to ME functionality:
+CME ERROR: <err>
Note: The Command is writing only.
Parameters
<dtmf-string> which has a max length of 20 characters, must be entered
between double quotes ("") and consists of combinations of the following
separated by commas. But a single character does not require quotes.
1) <dtmf> A single ASCII characters in the set 0-9, #,*, A-D. This is
interpreted as a sequence of DTMF tones whose duration is set by the
+VTD Command.
2) {<dtmf>, <duration>} This is interpreted as a DTMF tone whose
duration is determined by <duration>.
<duration> duration of the tone in 1/10 seconds range :1-255
Reference
GSM 07.07 [13]
Note
3.2.42 AT+CMUX Multiplexer Control
AT+CMUX Multiplexer Control
Response
+CMUX: list of supported (<mode>s),(<subset>s),(<port_spe
ed>s),(<N1>s),(<T1>s),(<N2>s),(<T2>s),(<T3>s),(<k>s)
OK
Test Command
AT+CMUX=?
Parameters
See Write Command
Read Command
AT+CMUX ?
Response:
+CMUX:[<mode>[,<subset>[,<port_speed>[,<N1>[,<T1>[,<N2>[,<T2
>[,<T3>[,<k>]]]]]]]]]