Tributary Switch; Satellite Switch; Ccsa Tandem Switch; Supervision - Avaya Communication Server 1000 Series Reference

Tributary switch

A tributary switch is a circuit switch that has a trunk route to a main circuit switch, but not to a
node. A tributary circuit switch can have CO, FX, and WATS trunks, as well as TIE Trunks to
other switches.

Satellite switch

The only difference between a satellite and tributary circuit switch is that the satellite switch
has neither incoming CO trunks nor attendant service. In this document, satellite and tributary
circuit switches are treated the same.

CCSA tandem switch

A Common Control Switching Arrangement (CCSA) tandem switch is the major switching
vehicle in a CCSA network. It is intended for very large systems. In a CCSA system, any end
user can reach any other global end user by dialing seven digits. The tandem switch performs
trunk-to-trunk switching only. Its function is similar to that of an ESN node, except that an ESN
node can support telephones in addition to trunk-to-trunk switching. Switches with TIE Trunks
to the tandem switch are called main switches. The CCSA network supports a dialing plan
similar to the ESN Uniform Dialing Plan (UDP).
The CCSA tandem switch is the interface point between the ESN network and a CCSA
network. The two networks can be arranged to function as a single integrated network.

Supervision

Supervision is a binary signal associated with each direction of transmission on a trunk facility.
The two states are on-hook and off-hook, similar to the condition of a telephone on-hook (hung
up) or off-hook (in use).
Each switch connected to a trunk sends a supervision signal to, and receives a supervision
signal from, the connected switch. Thus, the trunk has four supervision states. The trunk is idle
when both directions are on-hook. Off-hook is sent when a call is initiated on an idle trunk. This
action is called " seizing" the trunk. The distant switch receives the off-hook signal and prepares
to receive digits. A momentary off-hook condition returned from the destination switch can
occur during call setup, but a steady off-hook is not transmitted until the called telephone
answers. This off-hook signal is called "answer supervision." The supervision changes to on-
hook when the called telephone hangs up or is disconnected.
Electronic Switched Network Reference — Signaling and Transmission
Supervision
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