> 2.15 | AT^SM20 Set M20 compatibility mode

> M20 is an earlier, widely used SIEMENS GSM engine. The AT^SM20 command selects different modes of responses returned upon execution of the commands ATD and sms commands like e.g. AT+CMGW. Please note that the AT^SM20 command has no effect on any other features and is not intended to adjust other differences between M20 and TC65.
> Syntax

> Test Command AT^SM20=?
> Response(s)
> OK

> Read Command AT^SM20?
> Response(s)
> ^SM20:<CallMode>, <CmgwMode>
> OK

> Write Command AT^SM20=<CallMode>[, <CmgwMode>]
> Response(s)
> OK

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

> Parameter Description

> <CallMode>(num)

> Call setup response mode
> Applies only to voice calls.
> 0
> Set compatibility to Siemens mobile phones.
> ME will return "OK" immediately after attempting a call with the ATD command. In case of failure, additional call release indications, such as "NO DIAL TONE, "NO CARRIER", "BUSY" will follow.
> 1(&F)
> Default call setup mode, compatible to M20.
> ME will return "OK" in case of a successful connection, otherwise one of the call release indications "NO DIAL TONE, "NO CARRIER", "BUSY" are indicated.

> <CmgwMode>(num)

> Response mode for sending and writing short messages
> Applies to the sms commands like e.g. AT+CMGS and AT+CMGW command.
> 0
> Set compatibility to Siemens mobile phones.
> ME will return +CMS ERROR: <err> when writing or sending of short messages fails.
> 1(&F)
> Default mode for sending and writing short messages, compatible to M20.
> ME will return "OK", no matter whether or not sms command was successfully executed.