Может попробовать поднять трубку эмулируя нажатия кнопки?
попробуй команду
Keypad Control +CKPD
Description: This command emulates the MS keypad by sending each keystroke as a character in a
<keys> string.

If emulation fails, a +CME ERROR: <err> is returned. If emulation succeeds, the result
depends on the CDMA sequence activated: <keys>: string of the following characters (0-
9,*,#).

Syntax: Command syntax: AT+CKPD=<keys>
Command Possible Responses
AT+CKPD=”*#21#”
Note: Key sequence allowed
OK
AT+CKPD=1234
Note: Sequence not allowed
+CME ERROR 3