What is a USOC Jack?
The USOC is basically a naming convention for registered jack (RJ) wiring configurations used in telephone jacks or connectors that are still in active use today.
What does USOC mean in electrical wiring?
NOTE: The type of wiring shown here is known as USOC (pronounced U-sock). See background below. The secondary circuit is wired to the two pins (pins 2 & 5) directly to the side of the center pins and is the white/orange and orange/white pair (AKA: T2 & R2 - tip 2 and ring 2).
What is the universal service ordering code (USOC)?
The Universal Service Ordering Code serves to identify telecommunication services equipment. This was developed by Bell Systems and introduced in the 1970s by AT&T in order to connect telecommunications equipment in customer premises into the public network lines so that they can receive telephone services.
What is the difference between USOC RJ and RJ11?
The USOC standards consisted of many different Registered Jack Configurations which were abbreviated as "RJ" and had designations like RJ-11, RJ-12, etc. Today we still refer to modular jacks in the RJ designations but rarely use them to refer to a wiring standard that they were originally intended for.
What is UTP cable?
Most cable nowadays is UTP (unshielded twisted pair). There may be instances where you may need to connect to or transpose from the old "quad" cable. The diagram below provides the transposition between these standards.
What is the secondary circuit on a phone?
The secondary circuit is wired to the two pins (pins 2 & 5) directly to the side of the center pins and is the white/orange and orange/white pair (AKA: T2 & R2 - tip 2 and ring 2). Depending on the application, the secondary circuit can either be the 2nd dial tone line on a two line phone, or the data/control circuit for an electronic key phone.
What is the tip of a phono plug?
In telephony the terms that represent the conductors that comprise a circuit are known as "tip and ring". These terms stem from the early days of telephony when operators made telephone connections using 1/4" phono plugs similar to those used today for stereo headphones. The old systems also carried a third wire which was a ground. The "Tip" was the tip of the plug and was the positive (+) side of the circuit. The "Ring" was a conductive ring right behind the tip of the plug and was the negative (-) side of the circuit. Right behind the ring was the "Sleeve" which was the ground connection.
What is the ring on a plug?
The "Ring" was a conductive ring right behind the tip of the plug and was the negative (-) side of the circuit. Right behind the ring was the "Sleeve" which was the ground connection. The ground (sleeve) is no longer used today for individual pairs.
Is the ground used for pairs?
The ground (sleeve) is no longer used today for individual pairs.
