Telephony Primer PP.

Question 1

What does PSTN stand for?

Answer 1

Public Switched Telephone Network

Consists of all the equipment, facilities and connections maintained by all local and long distance carriers. (TELUS, BELL, etc)

Question 2

What does POT stand for?

Answer 2

Plain Old telephone services/system

Question 3

Voltage levels of a POTS line

Answer 3

Tip = 0V Ring = -48VDC
This negative charge helps. to impede corrosion in the cables and connections

The Ring signal, which was once used to power
mechanical ringers on phones, varies from about 80
to 105 volts AC, at 20 to 40Hz.

Question 4

Explain Demarcation in telephone lines

Answer 4

The termination point where the local exchange carrier (LEC) brings it’s lines to a customer. Typically the LEC is responsible for all equipment up to and including the Demarc.

Question 5

What is a Local Loop

====Will be on Final====

Answer 5

The Local Loop, or last mile, is the physical connection between the customer’s site, and the central office. This connection requires a dedicated pair of wires to form a circuit between the CO equipment and the customer equipment.

Most expansive to maintain
Is the most prone to damage

Question 6

Central Office

Answer 6

Building that contains the switching equipment that feeds the local loop.

Several COs connected by trunk cables

Question 7

What does Switch Equipment provide

Answer 7

it is at the CO
provides==================
-Dial Tone
-Call Setup
-Routing
-Caller ID, etc.

Question 8

Explain Trunks Cables

Answer 8

Connection between Central Offices

Traffic over Trunk lines must be multiplexed

Question 9

What is the signaling on a local loop called

Answer 9

In-Band Signaling

Signaling travels in the same path as the voice.
Caller ID
DTMF
Dial tone