Interfacing to parallax 27997 transceiver

Hello All, I have two of these transceiver. I had them hooked up to 2 basic stamps and they worked very well. Recently I bought an arduino 1280. C++ is a new language for me. So far things have gone pretty smooth. But I cannot get these transceivers to work. They are pretty simple, +5v, gnd and a serial input. I am connecting the trx pin of the 27997 to arduino trx pin 1 and using 2400 baud. Here are some snippets of code.

int rxPin = 0; int txPin = 1; pinMode(rxPin, INPUT); pinMode(txPin, OUTPUT);

Serial.begin(2400); Serial.print("A"); Serial.println();

I've spent most of the day trying different things but so far no success. I would welcome any suggestions.


data sheet for transceiver is here:


They are pretty simple, +5v, gnd and a serial input. I am connecting the trx pin of the 27997 to arduino trx pin 1

None of my Arduinos have a trx pin. Each one has a TX pin and each one has an RX pin. I think you need to be clearer exactly how you have the RF transceiver connected.

Pins 0 and 1 are already used by the Arduino for programming and communication with the PC over the USB port. It's best to leave these pins alone.

I suggest using the SoftwareSerial library to implement a "soft" serial port for this purpose:

-- The Gadget Shield: accelerometer, RGB LED, IR transmit/receive, light sensor, potentiometers, pushbuttons

Hi PaulS, Sorry for the typo. On the Arduino 1280 I am using the TX pin not the TRX pin The TX pin is pin #1. On the 27997 I am using the TXD pin. The TX(pin 1) on the Arduino is connected thru a 220 ohm resistor to the TXD pin on the 27997. Hope this is a little clearer. Once I get it working I can look at moving it to another pin on the Arduino. Thanks for your input.


Hi RuggedCircuits, I did try it on the TX1(pin18) on the arduino but didn't have any better results. It may have something to do with the data rate but I don't have much experience to rely on. On the basic stamp I had to use an inverted data rate which was 17197 to correspond to 2400 baud. Thanks for your suggestions.


TN - Despite the helpful tips you just received regarding the nomenclature of the Tx & Rx pins, I don't think your dealing with a UART type of serial.

IOW, you should be able to use any pin - and to make it easier, there is a library (with examples) called Virtual Wire you should check out.

Enjoy the Arduino

Hi Sparks, Thanks for your help. I will check out your suggestion. In spite of this little problem I am really having a lot of fun with the arduino!