The TDM2 is a very simple 433MHz band radio data modem. It provides a medium ranged half duplex, transparent data link between a pair of 9600 baud RS232 ports without any additional interface circuitry
UHF Narrow Band FM Vibration immune Multi Channel Receiver
The HVR2 receiver is the high vibration resistant version of the low cost RLC2H receiver. Its unique local oscillator design makes the unit almost immune to mechanical vibrations below 500Hz