Siemens TC37 Module At Command Reference page 66

AT Command Set
Example 3
Example 4
Example 5
Example 6
TC3X_ATC_01_V04.00
+CCFC: 1,4,"+493012345678",145
OK
To deactivate CFU without specifying <class>:
at+ccfc=0,0
OK
To check whether CFU was successfully deactivated (note that the
destination number remains registered in the network when you disable CFU):
at+ccfc=0,2
+CCFC: 0,1,"+493012345678",145
+CCFC: 0,2,"+493012345678",145
+CCFC: 0,4,"+493012345678",145
OK
To erase the registered CFU destination number:
at+ccfc=0,4
OK
Now, when you check the status, no destination number will be indicated:
at+ccfc=0,2
+CCFC: 0,1
+CCFC: 0,2
+CCFC: 0,4
To query the status of CFU for all classes:
at+ccfc=0,2,,,255
+CCFC: 0,1
+CCFC: 0,2
+CCFC: 0,4
+CCFC: 0,8
+CCFC: 0,16
+CCFC: 0,32
+CCFC: 0,64
+CCFC: 0,128
OK
<reas>=4 or 5 cannot be used to query the status of all call forwarding
reasons (see also notes above):
at+ccfc=4,2
+CME error: operation not supported
at+ccfc=5,2
+CME error: operation not supported
Page 66 of 204 29.05.2002