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A serial connector which looks very much like a standard telephone connector, except it houses eight wires instead of four.

RJ-45s are typically found on computers either integrated into the mother board or on a NIC. Because they are so small they are often used on devices such as terminal servers that have many ports.

Ethernet (10baseT) and Token Ring sometimes use four wires of an RJ-45 plug, 100baseVG uses all eight. 100BaseTX uses the same four wires of the RJ-45 connector as 10baseT but the wire must be category 5 instead of category 3.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)


(Registered Jack-45) A common data networking interface that employs a cable of twisted wire pairs and an 8-pin modular jack. RJ-45 is used for Ethernet and Type 3 Token Ring networks. See cable categories and RJ-48.

RJ-45 Connectors
Eight-wire RJ-45 connectors are used with Ethernet and Type 3 Token Ring networks.

Variations of RJ-45
These are the variations of RJ-45 pins and wire colors.
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Expanding on the former PN-525U's array of inputs including DVI-D, Component Video and RS-232C for system control, the new PN-S525 adds an HDMI input for digital 1080p content as well as an RJ-45 LAN input, allowing the monitor to be controlled, monitored and have diagnostics performed from a central location.
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New Taipei City, Taiwan, August 26, 2016 --(PR.com)-- For the wide spread adoptions of edge security gateways and virtual CPE, Lanner, a global leader in network appliance design and manufacturing, has added NCA-1210, a compact desktop network platform based on Intel Atom C2358/C2558 CPU (codenamed "Rangeley"), Intel QuickAssist Technology, four RJ-45 GbE LANs and four antenna holes.
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This flexible neck camera offers high resolution output signals for RCA, USB, VGA and RJ-45 network connection.