Excellent — thanks for your help! As for the serial stuff, I’m taking your advice and opening up a ticket with multitech support.
Hello.
After much testing it seems like something happening on AT&T’s network. Their gateway is transcoding the dollar sign. If we use an M2M providers’ SIM card on the T-Mobile network, this doesn’t happen. I guess I need to take this one up with AT&T.
Hope this is helpful to someone else 🙂
Sorry for the long pause but this got put on our back burner for a little while and we just now revisited it. After an entire Saturday of poking this with a stick the problem actually appears to have been line feeds.
The F4 happily accepts an LF as the command terminator, the new modems do not. issuing the ATS3=013
command to the modem fixed the problem. I hop this helps others!