Sending AT Command to a USB-Connected GPRS Modem in C#

Question

Can anyone give me a good direction or guide on how I can access a GPRS modem that is connected to a Usb Port. Should I make a USB driver for my program to send AT command to the modem? or Is like a router where in i can access it using an IP address? thanks

score 4 · Accepted Answer · answered May 09 '11 at 13:05

4

If its recognised by windows as a modem then the required drivers should automatically present it as a serial port, just like any other modem & you can communicate with it using its port name & System.IO.Ports.SerialPort. If you want to access the AT/GSM command set there are libraries like GSMComm.

answered May 09 '11 at 13:05

Alex K.

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you are right. there is a driver to make the usb recognized as serial port. do you think this url is a good start? http://www.codeproject.com/KB/IP/Send_and_Read_SMS.aspx – h3n May 09 '11 at 13:17
It looks ok from the comments @ the bottom of the page, but the best way to tell is to try it – Alex K. May 09 '11 at 13:31
If you dont want to use readymade libraries then you can use DataReceived Event Handler of Serial port and develop your own custom driver for the GSM/GPRS. – Nitin Gupta Jun 27 '12 at 07:56

score 2 · Answer 2 · answered May 09 '11 at 12:56

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Typically, these devices mount themselves with a virtual serial port, that you can open, and send your commands to.

answered May 09 '11 at 12:56

Rowland Shaw

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score 0 · Answer 3 · answered Jan 13 '12 at 14:07

Probably not useful to anymore, but when I plug-in my USB GPRS Modem, and install the software/drivers that came along with it, it created a virtual COM port.

Though it keeps changing after every reboot. Following code works for me.

var port = new System.IO.Ports.SerialPort();
.
.
port.WriteLine("AT+CREG=2");

Sending AT Command to a USB-Connected GPRS Modem in C#

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