The RT9080 E&M Radio contains a VHF or UHF full duplex radio and an interface board. The interface board uses a microprocessor to control the radio and it provides a 4W E&M interface which is accessible on a DB-15 connector at the rear of the unit.

The audio levels are adjusted to +7dBm and –16dBm.

A ground on the E’ lead (pin 2 of the DB 15 connector) keys the transmitter.

Transmit 4W audio is on pins 4 and 12; level is preset for 3.5kHz deviation with +7dBm input.

Receive 4W audio is on pins 3 and 10; level is preset to –16dBm output at 3.5kHz deviation.

Receive COR activates the ‘M’ relay which places a short between pins 1 and 9 (‘M’ lead).