问题
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
回答1:
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.
回答2:
Typically, these devices mount themselves with a virtual serial port, that you can open, and send your commands to.
回答3:
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");
来源：https://stackoverflow.com/questions/5937119/sending-at-command-to-a-usb-connected-gprs-modem-in-c-sharp