Use Arduino as USB-to-serial converter

Sometimes, we need an USB-to-serial converter such as UartsBee V4 to test some commands , for example, test GRPS AT command without use Arduino as repeater, this method you don’t need to change the code every time you set baud rate of your GPRS. We only have an Arduino or Seeeduino on hand, don’t be worry, actually, Arduino and Seeeduino has of a build-in USB-to-serial converter, Atmega 16U2 of Arduino, FT232 of Seeeduino. We could directly use this build-in USB-to-serial by uploading a small code to Arduino.

//Function : Disable pin0/pin1 connection to USB-to-serial converter

void setup()
void loop()

Preparing :
1.Uploading the above code to Arduino and then plug your electronic module onto Arduino/Seeeduino.
2.Download the serial tool SSCOM on the link It is not always necessary, you could use whatever serial tool you are familiar with.

Usage :
1. Get started GPRS AT Command
Use jumpers to connect GRPS_RX to RX(D0) of Arduino and GPRS_TX to TX(D1) of Arduino. After plugging GPRS Shield to Arduino, open SSCOM and select the COM port corresponding to Arduino and GPRS default baud rate 19200, if you don’t know which COM port you use, disconnect Arduino to PC to see which is disappear. Clicking on Open Com and power up your GPRS , you will see GPRS echo displaying on serial monitor. Enjoy using GPRS AT Command refer to AT Command datasheet. These steps is the same as GPRS wiki tutorial, for more details, see

2. Get started with Seeed Bluetooth Command
The same as GPRS Shield, what you need to do is connect Bluetooth_RX to RX(D0) of Arduino and Bluetooth_TX to TX(D1) of Arduino and open SSCOM to use Bluetooth command, refer to the Bluetooth Command on … uction.pdf , note that, /r/n is necessary to send frond and behind of every command, select SendNew, before send command, we can send a Null first (SEND1 on SSCOM).

Thank you for this. May come in handy.