Ameritron amplifier transceiver keying interfaces are designed to protect expensive radios from damage by keying line transients and steady state current voltage. They will work with almost any transceiver without the need of the plug-and-play pre-wired cable. These advanced interfaces are compatible with all common radios and amplifiers, even though radios and amplifiers do not have standardized voltages, accessory plugs, or wiring. The input is designed to be compatible with any transmitter or transceiver, and the output is compatible with AC control lines or DC positive or negative amplifier control lines having up to 200 V of peak open circuit voltage and 300 mA of operating current. Amplifiers can damage radios if the amplifier uses a high relay control voltage, has voltage spikes, or draws excessive current on the relay control line. Such damage often appears as stuck or sticky transmit relays in exciters, or shorted transistors on transmit control lines. In cases where the radio is damaged, the system transmits normally, but the external amplifier stays locked in a transmit mode. This prevents receive signals from coming through the amplifier with normal levels whenever the amplifier is supposed to be in the unkeyed operating "bypass" mode. The Ameritron amplifier transceiver keying interfaces have many electrical advantages over conventional relay buffer systems. They have no moving parts, switch almost instantly, are noiseless, have very long life, and will not develop dirty contacts. The interfaces operate with any relay voltage (AC, positive, or negative) up to 200 peak volts and any relay current up to 300mA. They are especially suited for buffering vacuum relay QSK amplifiers, since they do not affect attack or release times in a deleterious manner. The Ameritron amplifier transceiver keying interfaces operate with transmitters or transceivers that pull amplifier control lines to ground or operate with positive or negative control voltages. They include one power connector cord and plug with red wire (+12 V), black wire (negative and ground), and three mono patch cords with phono (RCA) connectors on each end, designed to be used for relay, ALC, and amplifier control lines.