ARDUINO UNO AND GSM SHIELD ICOMSAT 1.1 SIM900

Official Hardware Retired GSM Shield
1

Hallo,
I need help guys am using arduino uno and icomsat 1.1 sim 900 and i want to send an sms but every time i try it tells me DB: NO RESP
and then
ERROR: SIM900 doesn't answer, check power and serial pins in GSM.cpp.
I have checked GSM.CPP and changed the serial pins to 4/5 and 3/4 txd/rxd respectively to no avail kindly help my project is due and this is driving me nuts....I have also used an external power supply of 9 volts but it still does the same?What should I use as the serial pins?

2

Have you check the jumper on GSM Shield? Let me know how it be..

3

Are you using a library for the ICOMSAT ? The internal GSM library only works with the Official Arduino GSMshield .....?