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Registered jack-45 (RJ45) refers to a cable termination specification that specifies physical male and female connectors and the pin assignments of wires-in telephone cables and other networks that use RJ45 connections.
RJ45 connections are also known as data jacks.
Registered jack-45 (RJ45) is an eight-wire connector used to connect computers on local area networks. They were initially used as a telephone-only standard, but have since been applied to high-speed modems and other computer networks.
The RJ-45 is often confused with the 8P8C standard which looks almost identical but has particular properties regarding signal loss as the cabling is always made up of twisted pairs, a noise cancelling technology. The most common confusion is where RJ-45 is thought to be the same as an Ethernet connector, which is actually an RJ45S (or 8P8C) connection. RJ-45 is a telephony specification and although the connectors are almost identical to 8P8C, they have different signal conduction characteristics.
The 8P8C standard connectors are commonly referred to as RJ-45S.