Abstract: A novel apparatus is provided for facilitating the transfer of signals from a computer for the external setting of reception frequency parameters and other operating conditions of a radio receiver having a memory which is programmable according to data in the form of an electric pulse signal. The apparatus includes an interface circuit operatively coupled between the computer and the memory of the receiver. The interface circuit converts respective signal levels of the data into the electric pulse signals enabling data transfer and communication between the computer and the memory of the receiver. An improved flat-type, reversible connector is used between the interface circuit and the receiver. The connector has upper and lower surface portions, and is operatively coupled to a receptacle in the receiver.

Abstract: A system for externally setting reception frequency parameters of a radio scanner having a memory which is programmable according to data in the form of an electric pulse signal generated according to a protocol by a computer. The system includes a computer, a stereo phone plug connected to the RS-232 port of the computer, and a scanner stereo phone jack which can receive both of the stereo phone plug and a monaural ear-phone plug. The stereo phone plug has a common electrode, a first signal electrode and a second signal electrode. The second signal electrode carries the data from the computer to the scanner. The stereo phone jack has a common electrode, a first signal electrode and a second signal electrode.

Abstract: In a radio of the type having a selectively operable transmitter portion and an associated receiver portion for two-way communication, such as a CB radio, plus an auxilliary receiver for reproducing auxilliary audio signals, such as an AM/FM radio, a system is provided for automatically interrupting the audio signal output of the auxilliary receiver whenever the transmitter portion is operated. When the transmit/receive switch is in the transmit position, an auxilliary electronic switch interrupts the audio output of the auxilliary receiver by by-passing to ground the audio signal input to the audio amplifier section of the auxilliary receiver.

Abstract: A variable impedance circuit is included between the antenna and the RF amplifier stage of a radio receiver portion of a transceiver and is responsive to a phase-inverted and amplified AGC signal to automatically protect the receiver from breaking down or otherwise malfunctioning when it receives an over-input or excessive input signal level. When the input signal level to the receiver is at the typical operating level, the circuit provides a substantially infinite impedance to ground so as not to interfere with signal transmission from the antenna to the input stage and the successive stages.

Abstract: A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises means for generating a first reference signal having a predetermined frequency and means, including at least two voltage controlled oscillators (VCO), a mixer, a programmable frequency divider, and a switch, for generating a second reference signal, with the mixer being coupled to the first reference signal generating means and being selectively coupled on one of the VCO's by the switch to generate an output signal having a frequency corresponding to the difference between the frequency of said first reference signal and the frequency of the selected variable-frequency oscillator.

Abstract: A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises two crystal-controlled reference signal oscillators. First and second controllable variable-frequency oscillators (VCO's), first and second mixers, and a programmable frequency divider, together generate first and second output signals, with the first mixer being coupled to the first crystal oscillator and to the first VCO to generate the first output signal having a frequency corresponding to the difference between the frequency of the first reference signal and that of the first VCO. The second mixer is coupled to the second crystal oscillator and to the second VCO to generate the second output signal which has a frequency corresponding to the difference between the frequency of the second reference signal and the frequency of the second VCO.