Download - MULTIPLEXING APPLICATION
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
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
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