How to connect between two modem

1.How to connect between two modem(Modem A and Modem B)

First check signal strength by AT+CSQ,

return: +CSQ:**,## OK,"**,##" range from "8-31,99" menas it works normal

AT+CPIN?  Check the SIM state

Return : +CPIN：READY  OK  (normal)

After check signal strength and SIM state are  OK, we can send AT command as follow:

(1).Set two modem mode: ATS0=1 (Automatic response mode)

(2).B modem dial A modem by phone number:   ATD13956555555  ,that means ATD+phone number.

If dial success,A modem will output “CONNECT” through COM,if A modem is busy,B modem ouput “BUSY” through COM.

After dial up success, two modem can go on data communication,you just need send data to Modem by COM.

When data transmission is over, both of two modem can hang up the connection, first input “+++”and Enter,after it return OK,input ATH command.