The public intercom is to point to: transmitted power is not more than 0.5 W, work in specified frequency wireless intercom, the radio transmitting frequency, the power of radio frequency technology indicators shall meet the following requirements:

1, working frequency (. 9000; 409. Units: MHz) : 409.7500, 409.7625, 409.7750, 409.7875, 409.8000, 409.8125, 409.8250, 409.8375, 409.8500, 409.8625, 409.8750, 409.8875, 4099125, 409.9250, 409.9375, 409.9500, 409.9625, 409.9750, 409.9875;

2, modulation mode: F3E;

3, effective radiated power (EIRP) : < 0.5 W;

4, emission frequency tolerance: "+ 5 PPM,

5, transmitter stray radiation: "fifty uw;

6, receiver stray radiation: "twenty nw;

7, channel spacing: 12.50 kHz.