Search results
Results from the WOW.Com Content Network
This requires either two separate radio channels or channel sharing methods such as time-division duplex (TDD) to carry the two directions of the conversation simultaneously on a single radio frequency. [2] The first two-way radio was an AM-only device introduced by the Galvin Manufacturing Corporation in 1940 for use by the police and military ...
Several hand-held Project 25 radios used around the world. Project 25 (P25 or APCO-25) is a suite of standards for interoperable digital two-way radio products. P25 was developed by public safety professionals in North America and has gained acceptance for public safety, security, public service, and commercial applications worldwide. [1]
Forest Industries Telecommunications (FIT) is a Federal Communications Commission (FCC) certified frequency coordinator [1] and a non-profit association.Established in 1947, [2] its members include those companies or individuals who employ or are eligible to use Land Mobile Radio Service (LMRS) two-way radios.
The frequencies which would have been the second frequencies on half-duplex channels are not used for marine purposes and can be used for other purposes that vary by country. For example, 161.000 to 161.450 MHz are part of the allocation to the Association of American Railroads channels used by railways in the US and Canada.
A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a talkgroup) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time ...
The General Mobile Radio Service (GMRS) is a land-mobile FM UHF radio service designed for short-range two-way voice communication and authorized under part 95 of the US FCC code. It requires a license in the United States, but some GMRS compatible equipment can be used license-free in Canada. The US GMRS license is issued for a period of 10 years.
Radio waves are defined by the ITU as: "electromagnetic waves of frequencies arbitrarily lower than 3000 GHz, propagated in space without artificial guide". [5] At the high frequency end the radio spectrum is bounded by the infrared band. The boundary between radio waves and infrared waves is defined at different frequencies in different ...
Two-Way Radio Narrowbanding refers to a U.S. Federal Communications Commission (FCC) Order issued in December 2004 requiring all CFR 47 Part 90 VHF (150–174 MHz) and UHF (421–470 MHz) PLMR (Private Land Mobile Radio) licensees operating legacy wideband (25 kHz bandwidth) voice or data/SCADA systems to migrate to narrowband (12.5 kHz bandwidth or equivalent) systems by 1 January 2013.