Editing Cable modem (section)

===MITRE Cablenet===
[[Internet Experiment Note|Internet Experiment Note (IEN)]] 96<ref name="IEN 96">[http://ftp.rfc-editor.org/in-notes/ien/ien96.txt IEN 96] - The [[MITRE]] Cablenet Project</ref> (1979) describes an early [[RF]] cable modem system. From pages 2 and 3 of IEN 96:
<blockquote>The Cable-Bus System

The MITRE/Washington Cablenet system is based on a technology developed at MITRE/Bedford. Similar cable-bus systems are in operation at a number of government sites, e.g. [[Walter Reed Army Hospital]], and the [[NASA]] [[Johnson Space Center]], but these are all standalone, local-only networks.

The system uses standard [[community antenna television]] (CATV) [[coaxial cable]] and microprocessor based Bus Interface Units (BIUs) to connect subscriber [[computer]]s and [[Terminal (telecommunication)|terminals]] to the cable. ... The cable bus consists of [[Four-wire circuit|two parallel]] coaxial cables, one inbound and the other outbound. The inbound cable and outbound cable are connected at one end, the [[Cable television headend|headend]], and [[Electrical termination|electrically terminated]] at their other ends. This architecture takes advantage of the well developed [[Simplex communication|unidirectional]] CATV [[Distribution amplifier|components]].<ref name="RF Micro Devices, Inc. Whitepaper Describing Historical CATV Components">{{cite web|url=http://www.piedmontscte.org/resources/CATV+Hybrid+Amplifier+Modules+Past$2C+Present$2C+FutureWP.pdf|title=RF Micro Devices, Inc. Whitepaper Describing Historical CATV Components|website=Piedmontscte.org|access-date=2016-08-03|quotation=Amplifiers are one of the common components used in CATV system}}</ref> The [[Network topology|topology]] is dendritic (i.e. [[Tree topology|branched like a tree]]).<br/>
...<br/>
The BIUs contain [[Radio Frequency]] (RF) modems which [[Modulation|modulate]] a [[carrier signal]] to transmit [[Digital signal (electronics)|digital]] [[Information theory|information]] using 1 [[MHz]] of the available [[Bandwidth (signal processing)|bandwidth]] in the 24&nbsp;MHz frequency range. The remainder of the 294&nbsp;MHz bandwidth can be used to carry other [[communication channel]]s, such as [[Terrestrial television|off-the-air]] [[NTSC|TV]], [[FM radio|FM]], [[Closed-circuit television|closed circuit TV]], or a [[Voice frequency|voice]] [[Digital Telephony|telephone system]], or, other digital channels. The [[Bit rate|data rate]] of our test-bed system is 307.2&nbsp;[[Kilobit per second|kbps]].</blockquote>