Tele-Communication (Telecom) Terms Glossary and Dictionary
50-Pin Telco, also known as RJ21, is a connector very common in 10BASE-T wiring. As opposed to the RJ45 connector, the 50-pin Telco connector concentrates up to 12 UTP connections onto one connection. This concentration of UTP ports is then broken out for connection to a punch-down block inside a building's wiring closet. 50-pin Telco connections provide a very clean, uncluttered interface to the building's wiring. 50-Pin Telco is used to attach 25 pairs of telephone wires. It is also used for SCSI-1 connections and is the 50-pin version of the widely-used centronics connector found on the back of PC printers.