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Selective calling. In a conventional, analog two-way radio system, a standard radio has noise squelch or carrier squelch, which allows a radio to receive all transmissions. Selective calling is used to address a subset of all two-way radios on a single radio frequency channel. Where more than one user is on the same channel (co-channel users ...
Motorola Minitor. Front view of the Minitor V pager. The Motorola Minitor is a portable, analog, receive only, voice pager typically carried by fire, rescue, and EMS personnel (both volunteer and career) to alert of emergencies. The Minitor, slightly smaller than a pack of cigarettes, is carried on a person and usually left in selective call mode.
A paging system alerts a pager (or group of pagers) by transmitting information over an RF channel, including an address and message information. This information is formatted using a paging protocol, such as 2-tone, 5/6-tone, GOLAY, POCSAG, FLEX, ERMES, or NTT. Two-way pagers and response pagers typically use the ReFLEX protocol.
Another widely used system is the Continuous Tone-Coded Squelch System (CTCSS) also referred to as subaudible tones or PL tones (a Motorola trademark). This uses single audio tones in the range from 67 to 257 Hz to address each message to a specific radio or a group (or fleet) of radios. Each radio or group is assigned a different tone frequency.
A Tone remote, also known as an EIA Tone remote, is a signaling system used to operate a two-way radio base station by some form of remote control. [1] [2] [3] A tone remote may be a stand-alone desktop device in a telephone housing with a speaker where the dial would have been located. It may look like a desk top base station.
C-QUAM. C-QUAM (Compatible QUadrature Amplitude Modulation) is the method of AM stereo broadcasting used in Canada, the United States and most other countries. It was invented in 1977 by Norman Parker, Francis Hilbert, and Yoshio Sakaie, and published in an IEEE journal . Using circuitry developed by Motorola, C-QUAM uses quadrature amplitude ...
Motorola’s Pageboy II was launched in 1975 for the United States and 1976 for Europe in various types. Pb II 5-tone only 68–88 MHz / 146–174 MHz (US and Eur). Pb II tone only for 5-tone 80,6–88 MHz / 146–174 MHz (US). Pb II tone & voice radio for 2-tone signalling systems 68–88 MHz / 146–174 MHz (US). Pb II A04FNC Series radio ...
The use of digital squelch on a channel that has existing tone squelch users precludes the use of the 131.8 and 136.5 Hz tones as the digital bit rate is 134.4 bits per second and the decoders set to those two tones will sense an intermittent signal (referred to in the two-way radio field as "falsing" the decoder).