10BASE5

10BASE5 (also known as thicknet) is the original "full spec" variant of Ethernet cable, using special cable similar to RG-8/U coaxial cable. This is a stiff, convert|0.375|in|sing=on diameter cable with an impedance of 50 ohms (Ω), a solid center conductor, a foam insulating filler, a shielding braid, and an outer jacket. The outer sheath is often yellow-to-orange/brown foam fluorinated ethylene propylene (for fire resistance) so it often is called "yellow cable", "orange hose", or sometimes humorously "frozen yellow garden hose". ["All-in-One Network+ Certification Exam Guide", Mike Meyers, 3rd Ed., McGraw-Hill, 2004, p. 79.] 10BASE5 has been superseded by other cabling and wireless networking media, though due to its original widespread deployment may still be in use in some installations.

Name origination

The name "10BASE5" is derived from several characteristics of the physical medium. The "10" refers to its transmission speed of 10 Mbit/s. The "BASE" is short for baseband signalling as opposed to broadband, and the "5" stands for the maximum segment length of convert|500|m.

Network design

The maximum practical number of nodes that can be connected to a 10BASE5 segment is limited to 100 and transceivers may be installed only at precise 2.5-metre intervals. This distance was chosen to "not" correspond to the wavelength of the signal; this ensures that the reflections from multiple taps are not in phase. [citation | title = IEEE Standard 802.3-1985 | pages = 121 | isbn = 0-471-82749-5 | publisher = IEEE] These suitable points are marked on the cable with black bands. The cable must be one linear run; T-connections are not allowed. A 50-ohm resistive terminator is required at each end of the cable.

Transceivers can be connected to cable segments with N connectors, or via a "vampire tap", which allows new nodes to be added while existing connections are live. A vampire tap clamps onto the cable, forcing a spike to pierce through the outer shielding to contact the inner conductor while other spikes bite into the outer braided shield. Care must be taken to keep the outer shield from touching the spike; installation kits include a "coring tool" to drill through the outer layers and a "braid pick" to clear stray pieces of the outer shield.

The transceivers connect to nodes using a connector called an Attachment Unit Interface (AUI), a 15-pin, two-row D-style connector, but using a sliding clip instead of screws for cable restraint. A multi-wire cable carries the connection between the transceiver and the node.

ee also

* 10BASE2 (thinnet)
* 10BASE-T
* EAD-socket
* Computer network
* Local area network

References