The PSTN

Telephone Network is defined as group of interconnected _______ and subscribers

• COs

• switches

• end offices

• all of the choices

The PSTN can be defined as ________ and facilities involved in connecting a calling telephone to the called telephone regardless of where it might be.

• companies

• providers

• COs

• organizations

In PSTN, connection takes place in many levels that involve an array of systems and _________.

• technologies

• devices

• subcribers

• techniques

It consists of basic circuits that power the telephones and provides all the basic functions such as ringing, dial tone and dialing supervision

• signaling circuit

• BORSCHT

• SLIT

• Supervisor circuit

ON-HOOK means __________

• disconnected

• connected

• busy

• ringing

_________ is needed for long loop scale transmission

• Low-voltage

• High-current

• Low-current

• High-voltage

________ the ringer when picked up for use by a subscriber

• connects

• disconnects

• enables

• empowers

Functions that monitor local loop conditions and other services.

• control

• switching

• supervision

• over-voltage protection

functions that converts Analog to Digital, and vice versa

• Battery

• supervision

• testing

• coding

for simultaneous two-way conversation on a single pair of wires.

• hybrid

• supervision

• interface

• transformer