Editing Point-to-point (telecommunications) (section)

==Modern links==
[[File:CableFree_MMW_Link_installed_in_UAE.jpg|thumb|right|A 1&nbsp;Gbit/s point-to-point [[millimeter-wave]] link installed in the [[UAE]]]]
[[File:Locale_RS6_RADWIN-point-to-point-wireless-Huntington-Beach.jpg|thumb|A point-to-point wireless unit with a built-in antenna at [[Huntington Beach, California]]]]

With the exception of [[passive optical network]]s, modern [[Ethernet]] is exclusively point-to-point on the [[physical layer]] – any cable only connects two devices. The term point-to-point telecommunications can also mean a [[wireless networking|wireless]] data link between two fixed points. The wireless communication is typically bi-directional and either ''[[time-division multiple access]]'' (TDMA) or [[Channelization (telecommunications)|channelized]]. This can be a [[microwave relay]] link consisting of a transmitter which transmits a narrow beam of microwaves with a [[parabolic antenna|parabolic dish]] antenna to a second parabolic dish at the receiver. It also includes technologies such as [[laser]]s which transmit data modulated on a light beam. These technologies require an unobstructed [[line-of-sight propagation|line of sight]] between the two points and thus are limited by the visual horizon to distances of about {{convert|40|mi|km|abbr=}}.{{efn|The [[Telecommunications Industry Association]]'s engineering committees develop U.S. standards for point-to-point communications and related cellular tower structures.<ref>{{cite web|url=http://www.tiaonline.org/standards/committees/committee.cfm?comm=tr-14|title=TR-14 {{!}} Structural Standards for Communication and Small Wind Turbine Support Structures|work=Telecommunications Industry Association|access-date=2011-11-20|archive-url=https://web.archive.org/web/20140107033301/http://www.tiaonline.org/standards/committees/committee.cfm?comm=tr-14|archive-date=2014-01-07|url-status=dead}}</ref>  Online tools help users find if they have such line of sight.<ref>{{cite web |title= PtP Estimator Overview |publisher= AlphiMAX |url= http://www.alphimax.com/ptp |access-date= August 29, 2011 }}</ref>}}