Siemens TC37 Module At Command Reference page 102

AT Command Set
Note that the PIN2 authentication remains active for 300s. This means, for
example, that PIN2 will be requested once again, when you try to edit the "FD"
phonebook later than 300s after PIN2 authentication has been done.
Example 1
To change PIN2:
AT+CPWD=P2,0000,8888
Example 2 To write to "FD" phonebook:
AT+CBPS="FD"
OK
AT+CPBW=2,"+493012345678",145,"Charly"
+CME Error 17 (access denied due to missing PIN2 authentication)
AT+CPIN2=8888
OK
AT+CPBW=2,"+493012345678",145,"Charly"
OK
Example 3
To change price per unit:
AT+CPUC="dm","5",8888
TC3X_ATC_01_V04.00
(where 0000 = old PIN2 and 8888 = new PIN2)
Page 102 of 204 29.05.2002