I'm working on a SMS daemon for sending and receiving SMS. I'm using a (slightly modified) version of python-gsmmodem-new as my GSM-Library.
The problem I encountered was that with every Message a Delivery Report seems to be requested.
The strange thing is, the reports are seemingly disabled at modem initialization. I double checked the code, it's using the command
AT+CSMP=17,167,0,0
for initialization, which should be alright. After consulting the GSM Documentation I learned that for Delivery Reports Bit 5 has to be set, which is 32 in decimal, so the code for Delivery reports has to be AT+CSMP=49,167,0,0.
Is there something I could have missed?
As my Service Provider charges 25 cents per Report and there are roughly 800 Message per Month this is quite costly, and i can't really charge this to the customer :).
I solved it. The CSMP-setting was correct, but for whatever reason i had to set the modem into text mode with AT+CMGF=1 for it to work properly.
AT Command to disable delivery reports