> 18.7 | AT+VTS DTMF and tone generation

> AT+VTS is intended to send ASCII characters or strings which cause the Mobile Switching Center (MSC) to transmit DTMF tones to a remote subscriber. The command can only be used during active voice calls and offers the following variants:

> • | AT+VTS=<dtmfString> allows to send a sequence of DTMF tones with a duration defined with AT+VTD.

> • | AT+VTS=<dtmf>[,<duration>] allows to send a single DTMF tone. In this case, the duration can be indvidually determined during the call.

> Syntax

> Test Command AT+VTS=?
> Response(s)
> +VTS: (list of supported<dtmf>s), (list of supported<duration>s)
> OK

> Write Command AT+VTS=<dtmfString>
> Response(s)
> OK

> Write Command AT+VTS=<dtmf>[, <duration>]
> Response(s)
> OK
> ERROR
> +CME ERROR

> Reference(s) |  | PIN |  | ASC0 | ASC1 | USB | MUX1 | MUX2 | MUX3 |  |  | Charge | Q | Last
> GSM 07.07 |  | - |  | + | + | + | + | + | + |  |  | - | - | -

> Parameter Description

> <dtmfString>(str)

> String of ASCII characters in the set 0-9,#,*,A, B, C, D. Maximal length of the string is 29. The string must be enclosed in quotation marks ("...").

> <dtmf>(str)

> ASCII character in the set 0...9,#,*, A, B, C, D.

> <duration>(num)

> Tone duration in 1/10 seconds with tolerance. If not specified current setting of AT+VTD is used.
> The minimum duration of DTMF signals is 300ms.
> 1...255