Editing Last mile (telecommunications) (section)

===Wired systems (including optical fiber)===
Wired systems provide guided conduits for Information-Carrying Energy (ICE). They all have some degree of shielding, which limits their susceptibility to external noise sources. These transmission lines have losses which are proportional to length. Without the addition of periodic amplification, there is some maximum length beyond which all of these systems fail to deliver an adequate S/N ratio to support information flow. Dielectric [[Fiber to the x|optical fiber]] systems support heavier flow at higher cost.

====Local area networks (LAN)====
Traditional wired [[local area network]]ing systems require copper coaxial cable or a twisted pair to be run between or among two or more of the nodes in the network. Common systems operate at 100&nbsp;Mbit/s, and newer ones also support 1000&nbsp;Mbit/s or more. While length may be limited by [[collision detection]] and avoidance requirements, signal loss and reflections over these lines also define a maximum distance. The decrease in information capacity made available to an individual user is roughly proportional to the number of users sharing a LAN.

====Telephone====
In the late 20th century, improvements in the use of existing copper telephone lines increased their capabilities if maximum line length is controlled. With support for higher transmission bandwidth and improved modulation, these [[digital subscriber line]] schemes have increased capability 20-50 times as compared to the previous [[voiceband]] systems. These methods are not based on altering the fundamental physical properties and limitations of the medium, which, apart from the introduction of [[twisted pair]]s, are no different today than when the first telephone exchange was opened in 1877 by the Bell Telephone Company.<ref name="nxtbook">{{cite web|url=http://www.nxtbook.com/nxtbooks/natoa/journal_2009spring/index.php#/14|title=NATOA Journal - Spring 2009}}</ref>

The history and long life of copper-based communications infrastructure is both a testament to the ability to derive new value from simple concepts through technological innovation&nbsp;– and a warning that copper communications infrastructure is beginning to offer [[diminishing returns]] for continued investment.<ref name="nxtbook" /> However one of the largest costs associated with maintaining an ageing copper infrastructure is that of truck roll<ref>{{Cite news|url=https://multi-link.net/how-much-does-a-service-truck-roll-cost-your-company/|title=How much does a service "truck roll" cost your company? • Multi-Link Inc.|date=2015-04-16|work=Multi-Link Inc|access-date=2017-05-23|language=en-US}}</ref> - sending engineers to physically test, repair, replace and provide new copper connections, and this cost is particularly prevalent in providing rural broadband service over copper.<ref>{{Cite web|url=http://www.ispreview.co.uk/index.php/2016/05/aaisp-struggles-cost-keeping-uk-rural-broadband-alive.html|title=UK ISPs Struggle with the Cost of Keeping 20CN Rural Broadband Alive - ISPreview UK|last=Jackson|first=Mark|website=www.ispreview.co.uk|date=25 May 2016 |access-date=2017-05-23}}</ref> New technologies such as G.Fast and VDSL2 offer viable high speed solutions to rural broadband provision over existing copper. In light of this many companies have developed automated cross connects (cabinet based automated distribution frames) to eliminate the uncertainty and cost associated with maintaining broadband services over existing copper, these systems usually incorporate some form of automated switching and some include test functionality allowing an ISP representative to complete operations previously requiring a site visit (truck roll) from the central office via a web interface.<ref>{{Citation|last=UTEL (United Technologists Europe Limited)|title=RoboCab - Full cabinet automation (Auto PCP / AMDF)|date=2017-03-03|url=https://www.youtube.com/watch?v=klHZG4ybmxU |archive-url=https://ghostarchive.org/varchive/youtube/20211212/klHZG4ybmxU| archive-date=2021-12-12 |url-status=live|access-date=2017-05-23}}{{cbignore}}</ref> In many countries the last mile link which connects landline business telephone customers to the local [[telephone exchange]] is often an [[ISDN30]] which can carry 30 simultaneous telephone calls.

====CATV====
Community antenna television systems, also known as [[cable television]], have been expanded to provide bidirectional communication over existing physical cables. However, they are by nature shared systems and the spectrum available for reverse information flow and achievable [[signal-to-noise ratio|S/N]] are limited. As was done for initial unidirectional TV communication, cable loss is mitigated through the use of periodic amplifiers within the system. These factors set an upper limit on per-user information capacity, particularly when many users share a common section of cable or [[access network]].

====Optical fiber====
{{Further|Optical fiber}}
Fiber offers high information capacity and after the turn of the 21st century became the deployed medium of choice ("[[Fiber to the x|Fiber to the ''x'']]") given its scalability in the face of the increasing bandwidth requirements of modern applications.

In 2004, according to Richard Lynch, Executive Vice President and Chief Technology Officer of the telecom giant [[Verizon]], the company saw the world moving toward vastly higher bandwidth applications as consumers loved everything broadband had to offer and eagerly devoured as much as they could get, including two-way, user-generated content. Copper and coaxial networks would not&nbsp;– in fact, could not&nbsp;– satisfy these demands, which precipitated Verizon's aggressive move into [[Fiber to the x|fiber-to-the-home]] via [[FiOS]].<ref>{{cite web|url=http://www22.verizon.com/Content/ExecutiveCenter/Richard_Lynch/ftth_conference_expo/ftth_conference_expo.htm|title=Verizon Leadership Executive Biographies - Verizon}}</ref>

Fiber is a [[future-proof]] technology that meets the needs of today's users, but unlike other copper-based and wireless last-mile mediums, also has the capacity for years to come, by upgrading the end-point optics and electronics without changing the fiber infrastructure. The fiber itself is installed on existing pole or conduit infrastructure and most of the cost is in labor, providing good regional [[economic stimulus]] in the deployment phase and providing a critical foundation for future regional commerce.

[[fixed line|Fixed copper lines]] have been subject to theft due to the value of copper, but optical fibers make unattractive targets. Optical fibers cannot be converted into anything else, whereas [[Copper#Recycling|copper can be recycled without loss]].