L7 - Public Switched Telephone Network(PSTN Historical...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Public Switched Telephone Network (PSTN) Historical developments: Insert Fig. 2-20 a) Wire between any pairs of telephones (1877) b) Switching office introduced (1878) b to c) Connect any pair of offices, but then connect to a second-level switching network. Hierarchy eventually grew to five levels. General model maintained 1890-1984.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Makeup of communication paths in the telephone network Insert Figure 2-21 Local loops - category 3 twisted pairs connect a telephone and an end office. Analog signals in 300-4000 hz range. All trunks and switches use digital transmission. Connections: coaxial cable, microwave beams, fiber optic cables. Digital transmission was important for its regeneration advantage (even when all traffic was voice).
Background image of page 2
Changes from the 1984 Bell System breakup. most local and long distance service.This was judged a monopoly and broken up. Operating Companies. U.S. was divided into 164 Local Access and Transport Areas (LATA), with one Local Exchange Carrier (LEC) in each. Insert Fig. 2-22
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
able to compete as IntereXchange carrier (IXC) among LATA’s. (WorldCom, Sprint) For fairness, each had to have a point of presence (POP) in each LATA. Initially, all IXC’s couldn’t offer local service, and
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/23/2009 for the course CMPEN 362 taught by Professor Johnmetzner during the Spring '09 term at Penn State.

Page1 / 14

L7 - Public Switched Telephone Network(PSTN Historical...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online