Editing Packet radio (section)

== History ==

Earlier [[digital radio]] communications modes were [[telegraphy]] (using [[Morse code]]), [[teleprinter]] (using [[Baudot code]]) and [[Fax|facsimile]].

=== Aloha and PRNET ===

Since radio [[Telecommunication circuit|circuits]] inherently possess a [[Broadcasting (computing)|broadcast]] [[network topology]] (i.e., many or all [[Node (networking)|nodes]] are connected to the [[Telecommunications network|network]] simultaneously), one of the first technical challenges faced in the implementation of packet radio networks was a means to control access to a shared [[communication channel]] to avoid collisions of signals. Professor [[Norman Abramson]] of the [[University of Hawaii]] led development of a packet radio network known as [[ALOHAnet]] and performed a number of experiments beginning in the 1970s to develop methods to arbitrate access to a shared radio channel by network nodes. This system operated on [[UHF]] frequencies at 9,600 baud. From this work the [[Aloha protocol|Aloha]] multiple access protocol was derived. Subsequent enhancements in channel access techniques made by [[Leonard Kleinrock]] ''et al.'' in 1975 would lead [[Robert Metcalfe]] to use [[carrier-sense multiple access]] (CSMA) protocols in the design of the now commonplace [[Ethernet]] [[local area network]] (LAN) technology.

Over 1973–76, [[DARPA]] created a packet radio network called [[PRNET]] in the [[San Francisco Bay]] area and conducted a series of experiments with [[SRI International|SRI]] to verify the use of [[ARPANET]] (a precursor to the [[Internet]]) [[Internet Protocol Suite|communications protocols]] (later known as [[Internet Protocol|IP]]) over packet radio links between mobile and fixed network nodes.<ref>Okin, J.R. (2005). ''The Internet Revolution: The Not-for-Dummies Guide to the History, Technology, and Use of the Internet'', p.81. Ironbound Press. {{ISBN|0-9763857-6-7}}.</ref> This system was quite advanced, as it made use of direct sequence [[spread spectrum]] (DSSS) modulation and forward error correction ([[Forward error correction|FEC]]) techniques to provide 100&nbsp;kbit/s and 400&nbsp;kbit/s data channels. These experiments were generally considered to be successful, and also marked the first demonstration of [[Internetworking]], as in these experiments data was routed between the ARPANET, PRNET, and [[SATNET]] (a satellite packet radio network) networks. Throughout the 1970s and 1980s, DARPA operated a number of terrestrial and satellite packet radio networks connected to the ARPANET at various military and government installations.

=== Amateur Packet Radio and the AMPRNet ===
{{Main|AMPRNet}}

[[Amateur radio]] operators began experimenting with packet radio in 1978, when—after obtaining authorization from the Canadian government—Robert Rouleau, VE2PY; Bram Frank, VE2BFH; Norm Pearl, VE2BQS; and Jacques Orsali, VE2EHP<ref>I wrote the code for the demo on May 31st 1978 at the M.A.R.C. meeting in Montreal</ref> of the Montreal Amateur Radio Club [[Montreal]], [[Quebec]], began experimenting with transmitting [[ASCII]] encoded data over [[VHF]] amateur radio frequencies using homebuilt equipment.<ref>Rouleau, Robert and Hodgson, Ian (1981). ''Packet Radio''. Tab Books, Blue Ridge Summit, PA. {{ISBN|0-8306-9628-8}}.</ref> In 1980, Doug Lockhart VE7APU, and the Vancouver Area Digital Communications Group (VADCG) in [[Vancouver]], British Columbia began producing standardized equipment ([[Terminal node controller|Terminal Node Controllers]]) in quantity for use in amateur packet radio networks. In 1989, Lockhart was inducted by the Canadian Amateur Radio Federation (CARF, now [[Radio Amateurs of Canada]]), as its First Member of the Canadian Amateur Radio Hall of Fame (CARHOF) for his outstanding contribution to the development of Amateur Packet Radio Communications.<ref>https://www.rac.ca/carhof/canadian-amateur-radio-hall-of-fame-1989-doug-lockart-ve7apu/</ref>  In 2003, Rouleau was inducted into [[CQ Amateur Radio]] magazine's hall of fame for his work on the Montreal Protocol in 1978.<ref>{{cite web|title=The CQ Amateur Radio Hall of Fame|publisher=[[CQ Amateur Radio]]|date=June 2007|url=http://www.cq-amateur-radio.com/AmateurRadioHofFMay2907.pdf|access-date=2009-05-02|archive-url=https://web.archive.org/web/20081203062737/http://www.cq-amateur-radio.com/AmateurRadioHofFMay2907.pdf|archive-date=2008-12-03|url-status=dead}}</ref>

Not long after this activity began in Canada, amateurs in the US became interested in packet radio. In 1980, the United States [[Federal Communications Commission]] (FCC) granted authorization for United States amateurs to transmit ASCII codes via amateur radio.<ref name=chron>{{cite web| last=Mendelsohn |first=Alex |url=http://www.n1fd.org/bulls/2000/0005/dxrx.html |title=Amateur Packet – A Brief Chronology: Phase 1 (1970–1986) |access-date=2009-08-09 |archive-url=https://web.archive.org/web/20010129134100/http://www.n1fd.org/bulls/2000/0005/dxrx.html |archive-date=2001-01-29}} See ''FCC Gives The Nod'' and ''Making Modifications''</ref> Repeaters may be designed for amateur packet radio, these are dubbed "digipeaters". The first known amateur packet radio activity in the US occurred in [[San Francisco]] during December 1980, when a packet repeater was put into operation on [[2 meters]] by [[Hank Magnuski]] KA6M, and the Pacific Packet Radio Society (PPRS).<ref>Kenney, Larry [http://www.choisser.com/packet/part01.html "Introduction to Packet Radio – Part 1"], "A Short History – How it all began". Retrieved 2009-08-09.</ref> In keeping with the dominance of DARPA and ARPANET at the time, the nascent amateur packet radio network was dubbed the [[AMPRNet]] in DARPA style.{{citation needed|date=January 2014}} Magnuski obtained [[IP address]] allocations in the [[44.0.0.0/8|{{IPaddr|44.0.0.0|8}} network]] for amateur radio use worldwide.

Many groups of amateur radio operators interested in packet radio soon formed throughout the country including the Pacific Packet Radio Society (PPRS) in [[California]], the [[Tucson Amateur Packet Radio Corporation]] (TAPR) in [[Arizona]] and the Amateur Radio Research and Development Corporation (AMRAD) in [[Washington, D.C.]]<ref>American Radio Relay League (2008). "ARRL's VHF Digital Handbook", pp. 1–2, American Radio Relay League. {{ISBN|0-87259-122-0}}.</ref>

By 1983, TAPR was offering the first TNC available in kit form. Packet radio started becoming more and more popular across [[North America]] and by 1984 the first packet-based [[bulletin board system]]s began to appear. Packet radio proved its value for emergency operations following the [[Aeroméxico Flight 498|crash of an Aeromexico]] airliner in a neighborhood in [[Cerritos, California]], in August 1986. Volunteers linked several key sites to pass text traffic via packet radio which kept voice frequencies clear.

For an objective description of early developments in amateur packet radio, refer to the article "Packet Radio in the Amateur Service".<ref>Karn, P. Price H. Diersing, R. (May 1985). "Packet Radio in the Amateur Service", pp. 431–439, "IEEE Journal on Selected Areas in Communications". ISSN 0733-8716.</ref><ref name=chron />