FXT009: problem sending SMS using GSMComm library

I bought the FXT009 to send and receive SMS textmessages from my C# application.
To do this I downloaded the GSMComm library.
I installed the modem and driver + ran the GSMComm demo program.
I can connect to the modem (Com3) and all features work EXCEPT sending SMS-messages…
It throws the following error:

Error: The phone reports an unspecified error. This typically happens when a command is not supported by the device, a command is not valid for the current state or if a parameter is incorrect. (GsmComm.GsmCommunication.CommException)

Anybody any ideas?

Regards,
Koen

You need to study the GSMComm ]library documentation to understand exactly what commands it is sending, and what responses it is expecting - then verify that against the the AT commands documentation for the FXT.

Can you get the library to tell you what “unexpected” error, exactly, it is receiving?

Have you contacted the library’s authors?

Have you tried “spying” the comms?

https://forum.sierrawireless.com/t/gl6110-truncates-sms-received/6956/1
https://forum.sierrawireless.com/t/gl6110-truncates-sms-received/6956/1