Quote Originally Posted by Ioannis View Post
I would strongly suggest to use hardware USART and if possible interrupts like Darrels Instant Interrupts. It will assure you no lost characters.

Secondly, I see that you are not checking if the modem has replied with OK or an error, except once. Not all commands have the same processing time. So it is a good practise to confirm that the device has accepted succesfully the command by monitoring its response.

Ioannis
I've used an open source software called " real term" to test out the serial cable

The following are the codes i used to test:

Code:
    Serout2 Tx,84,["Ready:",13]
	pause 500
	Serin2 rx,84,[wait("A="),B0]				
	Pause 500
    Serout2 PORTC.6,84,["Got: ",B0,13]
	pause 500
	goto init
It's working. Now I need to test the GSM modem using SEROUT2 and SERIN2 commands. Anyone knows how?