Signshine Information--- FAQ for GPRS GSM SMS Modem

                         FAQ for SignShine GPRS GSM SMS Modem


  1. 1.Why GSM SMS modem cant send messages?

--Firstly to check whether AT command is workable, and signal is good enough, and SIM card is

  fastened well

--Enough charge for SIM card traffic?

--Modem baud rate right or not?Sim card short message center number right or not?

--Serial cable(rs232 cable),ok or not?


  1. 2.GPRS SMS Modem can send SMS but is unable to receive SMS

--To check whether the storage of Sim card/Module is full or not


  1. 3.When message stored in the Sim card,but unavailable to read?

--Setup AT^SSMSS=1 command for the modem



  1. 4.When I use 3G SMS modem for dial-up, it shows hardware conflict.

--Please check if  the COM port is occupied by other devices, baud rate is correct? or AT 

command is ok?Flow control shall be none

AT+CGDCONT=1,IP,CMNET shall be correctly filled when dial-up (CMNET is the APN of 

China Mobile, please fill your local APN)


  1. 5.Serial GSM SMS Modem shows error code 777, 743 when dial-up,and got approved

--Make sure enough the charge of SIM card traffic?  The signal is good enough?

You may reboot your PC or test it with another PC for dial up.


  1. 6.There have data loss when use GSM SMS Modem for sending messages to cell phone

--Use another serial tool for testing.

--Check if the baud rate and parity bit of serial tool is the same as S3320

--Check if sending format is accordance with display format.

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