MULTIPLEXING APPLICATION

The Telephone System

Telephone Network

Analog Switched Service

Analog Leased Service

Analog Hierarchy

Analog vs Digital

• Noise immunity– Noise is analog

• Cost– Digital: 2 signals– Analog: continuous range of signal

Switched/56 Service

Digital Service Unit (DSU) – changes the rate of data to 56 kbps-encodes the data in the format used by the service provider-More expensive than modem-Has better speed, quality less susceptible to noise

Digital data service-DDS

Maximum data rate – 64kbps

Digital signal (DS) Hierarchy

DS Hierarchy

• DS – 0– Single digital channel – 64kbps

• DS – 1– 24 * 64 kbps + 8 kbps overhead = 1.544Mbps– Or any combination that can fit within 1.544Mbps

• DS – 2– 96 * 64 kbps + 168 kbps overhead = 6.312 Mbps

• DS – 3– 672 * 64 kbps + 1.368 Mbps overhead = 44.376 Mbps

• DS – 4– 4032 * 64 kbps + 16.128 Mbps overhead = 274.176 Mbps

T-1 Line

T-1 Frame

Fractional T-1 Line

Digital Service Unit/Channel Service unit

DS & T Line Rates

Service Line Rate (Mbps)

Voice Channels

DS - 1 T - 1 1.544 24

DS - 2 T - 2 6.312 96

DS - 3 T - 3 44.736 672

DS - 4 T - 4 274.176 4032

E Line Rates

Line Rate (Mbps)

Voice Channels

E - 1 2.048 30

E - 2 8.448 120

E - 3 34.368 480

E - 4 139.264 1920