Edgar C.

#include <nRF905.h>
/*
 * Project: nRF905 AVR/Arduino Library/Driver
 * Author: Zak Kemble, me@zakkemble.co.uk
 * Copyright: (C) 2013 by Zak Kemble
 * License: GNU GPL v3 (see License.txt)
 */

/*
 * Wait for data and reply.
 * Output power is set to the lowest setting, receive sensitivity is
 * lowered.
 *
 * 7 -> CE
 * 8 -> PWR
 * 9 -> TXE
 * 2 -> CD
 * 3 -> DR
 * 10 -> CSN
 * 12 -> SO
 * 11 -> SI
 * 13 -> SCK
 */

#include <nRF905.h>
#include <SPI.h>

#define RXADDR 0x586F2E10 // Address of this device (4 bytes / long data type)
#define TXADDR 0xFE4CA6E5 // Address of device to send to (4 bytes / long data type)

void setup()
{
  // Start up
  nRF905_init();

  // Set address of this device
  nRF905_setRXAddress(RXADDR);

  // Lowest transmit level -10db
  nRF905_setTransmitPower(NRF905_PWR_n10);

  // Reduce receive sensitivity to save a few mA
  nRF905_setLowRxPower(NRF905_LOW_RX_ENABLE);

  // Put into receive mode
  nRF905_receive();

  Serial.begin(9600);

  Serial.println("Server started");
}

void loop()
{
  Serial.println("Waiting for data...");

  // Make buffer for data
  byte buffer[NRF905_MAX_PAYLOAD];

  // Wait for data
  while(!nRF905_getData(buffer, sizeof(buffer)));

  for (byte i=0; i<sizeof(buffer); i++){
    Serial.print((char)buffer[i]);
    Serial.print("-");
  }
  Serial.println();

  // Set address of device to send to
  nRF905_setTXAddress(TXADDR);

  // Set payload data (reply with data received)
  nRF905_setData(buffer, sizeof(buffer));

  // Send payload (send fails if other transmissions are going on, keep trying until success)
  while(!nRF905_send());

  // Put back into receive mode
  nRF905_receive();

  Serial.println("Got data");
}