"Connection mode" parameter group

Connection mode of the CP 1242-7

● Permanent

Continuous connection between the remote station and the telecontrol server.

Once the connection has been established, it should remain permanently established. If

the connection is interrupted, the remote station automatically attempts to re-establish the

connection.
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So, a wake-up SMS seems not required at all.

Do you use the latest FW of the CP? See link below.
http://support.automation.siemens.com/WW/view/en/58565570