After performing the pcb design of sim module , it works fine BUT after inserting sim card it reset periodically (after each 20 sec)and send 'Call Ready'
When I insert the card at no network coverage area it doesnt reset
Note : I dont use ESD but I think its not the reason ...
my operator:Vodafone EG
I also make short between RTS&CTS and bet. DTR&DCD ,Is it true ?