Wiring Connections: Hooking Things Up
The telco uses a variety of connections to bring the service to the customer locations. The typical connection is the two-wire service that we keep talking about. This two-wire interface to the network is terminated in a demarcation point as required by law. The DEMARC is the point of least penetration into the customer’s premises, typically within 12 of where the telco cable comes up into the building. Normally, telco terminates in a block; this can be the standard modular block for a single-line telephone. If the customer has multiple lines, telco will terminate in a 66 block, or an RJ21X. These are fancy names for their termination points.
The typical modular connector uses an RJ11C for telephones connected to a 2-pair interface (not to be confused with the two wires), or an RJ45X as a 4-pair interface for both voice and data. Another version of connector for digital service is an 8-conductor (4-pair), called the RJ48X.
When a telco brings in a digital circuit, it will terminate the 4-wire circuit into a newer RJ68 or a smart jack. There is no major mystique in any of these connectors. The number is strictly a uniform service code so that they can keep it all straight. However, when ordering a circuit, the telco will ask you how you want it terminated. The rule of thumb, in a multiline environment, is to use the RJ21X (which is a 66 block with an amphenol connector on it). Sounds complex, doesn’t it? A single line will terminate in an RJ-11C or RJ-12.
This introduction is meant to teach you about the functions and technology of a Central Office.
Sound
Analog to Digital
Bandwidth
Facilities Network
Traffic Networks
Public Switched
The Telephone Network
A Topology of Connection
Network Hierarchy (pre 1984)
Network Hierarchy (post 1984)
North American Numbering Plan
International Numbering
The Subscriber Extension
Private Networks
Hybrid Networks
Local Access and Transport Areas
Wiring Connections: Hooking Things Up
Types of Communication
Signaling (SS7)
Lines Vs. Trunks
Loop Start
Calling Procedures
Ground Start
E&M Signaling
Foreign Exchange Signal
DID
DOD
FX
OPX
Wats