Using GPRS in MF: How to Implement GPRS Modem dial-up Internet access through a serial port terminal

There is a GPRS Modem during the development of a. Net micro framework project. We provide 5 V voltage through the serial port on the motherboard.

GPRS modem design board

We use txd and rxd, which correspond to the com4 on another motherboard chip. When we start to implement the GPRS Modem dialing, I want to use the GSM 7.07 standard, on the objective term terminal, connect the serial port above the GPRS Modem through the stk500 Development Board, and then send a command to dial the internet.

Steps when dial up the GPRS Modem:

 

/* Steps when reset the GPRS Modem:
* 1. Check the PIN code, if need we update it, update the pin code.
* 2.ask for a disconnection.
* 3.set default connection.
* 4.set Flow Control. DTE-DCE the local flow control. Flow Control = none.
* 5.set PDP.
* 6. Dial specified PDP.
*/

 

So first send:,

Ask for a disconnection of all connections in GPRS Modem: ATH

Then, set the default parameter aiton: atz

This command can be softreset. If you want to restart the GPRS Modem hard, you still need to set it down on the reset foot once.

Then, set flow contrl, DTE-DCE local flow control, flow control = none,

At + IFC = 0, 0

Then set DCD signal to match the network data carrier.

At & C1.

Next, you can see if the SIM card needs to enter the PIN code. The first query is at + cpin?

Determine whether to enter the PIN code or not based on the corresponding results.

 

Then, the last two steps are left to set PDP and then dial the specified PDP:

At + cgdcont = 1, "ip", "cmnet"

Atdt * 99 *** 1 #

 

During the atdt connection, you can read the DCD pin to determine whether the connection is connected, and decide whether to switch to the PPP protocol for dialing.

Here, it actually means that the things described in this question are impossible. A serial port can use the AT command to connect to the network carrier, but you want to dial up the Internet successfully,

It is not possible to use the terminal because the PPP protocol is not implemented. However, you can use a terminal to connect to the network carrier.

 

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