I want to use Wavecom's TCP/IP stack, but it doesn't appear to be working/enabled on my modem.

All the GSM modems should have the stack.

Here is the procedure to test for presence of the stack:

1. Enter AT+WOPEN?
The response should be 0 or 1. If the response is ERROR, then the stack is not present.

2. If the response is 0, then enter AT+WOPEN=1 and proceed to the next step.

3. If the response is 1, then type AT#VVERSION (note that this is # followed by two V's, not a W). The response to the #VVERSION command should be a long string indicating the eDsoft version number. AN ERROR response, means the stack is not present.