Problem with GPRS shield (no communication at all)

[guan]

@jimbo.we

Sorry about the inconvenience. I think you can try to upgrade the firmware of SIM900, please down load the firmware and tool (including how) from : garden.seeedstudio.com/images/8/ … d_tool.zip

Thanks for the suggestion. I can’t quite get it to work, I get various different error messages and I’ve attached two.

I have connected pin 5 of the DB-9 RS-232 to ground, and pin 2 to the SIM900 board’s TX and pin 3 to the SIM900 board’s RX. (These pin numbers are looking into the male connectors on the computer end.)

Question: Is it ok to use the GPRS_TX and GPRS_RX pins on the SIM900 board, or do I need to use the actual TXD and RXD pins on the SIM900 chip itself?

Question: What is the exact procedure? I have tried various variations, but here’s what I am doing now:

1. Power on SIM900 board.
2. Press the power key, wait for the lights to be normal.
3. Press Start button in firmware update program.

I was not able to use the power key at all when GPRS_TX and GPRS_RX are connected.