Hi,
I have a function to send sms with hsdpa gsm, and a function for read recieve sms.
my program run and it works good, but after it sends 6 or 7 sms, my program can't connect to gsm modem.
The error is " port is already in use "
but after I stop it and run it again , it works good again for a few times.
each time these functions (send sms or recieve sms ) run, they open serial port at the first of function and then close the serial port when they finish sending or reading recives sms.
How can I solve this problem ?