SIM900 DCD line deasserted after CLOSED

[rgl]

Hi @all,

i have set up a transparent TCP/IP connection with the SIM900.
All data received (binary) is forwarded to a serial port.

When the TCP/IP connection is closed (by foreign host or mobile provider or whatever) the SIM900 sends CLOSED and DCD is deasserted. Unfortunately the CLOSED response starts before the DCD line is deasserted and therefore part of the CLOSED is send to the serial port as well.

Is there some way to circumvent this behaviour (without parsing the data stream)?
Is perhaps the new AT+CIPTXISS command related to this? If not what is this command doing?
Is the behaviour perhaps changed in later FW revisions (currently using 1137B07SIM900M64_ST)? By the way is it possible to find out if there are newer versions and what has been changed (i couldn't find anything on the sim.com website)?

Best regards,
rgl

 

[chipseller]

Hi RGL

Here is he latest build relevant to your current version, the release notes and the latest AT command reference manual. I cant be sure that this will fix your specific problem, but its worth a try.