Well, this is a Developer forum - yours seems to be a user question?
Have you read the Fastrack User Guide?
OK, what do you actually mean by “Connected” here?
The process is:
From one modem, you call the other with ATD;
The called modem indicates the incoming call with RING;
You type ATA at the called modem to answer the call;
Both modems say CONNECT
You are now in online (data) mode
This is exactly the same as for “normal” PSTN (wired) modems.
If you have doubts about the Fastrack modems, try it first between two PSTN modems;
Then try between one PSTN modem, and one Fastrack modem.