Communications System Owner Manual
Table Of Contents
- Table of Contents
- ABOUT THIS DOCUMENT
- 1. INTRODUCTION TO CONNECTIVITY
- 2. COMMUNICATION SYSTEM NETWORKING (em AN OVERVIEW
- 3. TANDEM TIE TRUNK NETWORKS
- 4. MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES
- 5. ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES
- 6. DISTRIBUTED COMMUNICATIONS SYSTEM (DCS)
- 7. DATA CONNECTIVITY - AN OVERVIEW
- 8. DATA COMMUNICATIONS CAPABILITIES
- 9. DATA COMMUNICATIONS CONFIGURATIONS
- A. RELATED DOCUMENTS
- B. SYNCHRONIZATION OF DIGITAL FACILITIES
- THE NEED FOR SYNCHRONIZATION
- SYNCHRONIZATION HIERARCHY
- CHANGES TO THE SCS SOFTWARE MADE AVAILABLE VIA SOFTWARE PATCHES
- NETWORK SYNCHRONIZATION AND ENGIINEERING
- AVAILABILITY OF SYNCHRONIZATION SOURCES
- CONCLUSIONS ON SYNCHRONIZATION
- USE OF GENERIC 2 AS A SYSTEM CLOCK REFERENCE
- USE OF GENERIC 1 AS A SYSTEM CLOCK REFERENCE
- C. TRUNKING TERMS AND CAPABILITIES
- D. COMMUNICATIONS PROTOCOLS
- E. LEAD DEFINITIONS
- F. NETWORKING FEATURES - AVAILABILITY MATRIX
- ABBREVIATIONS
- GLOSSARY
- INDEX
MULTIPLEXED COMMUNICATION
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As signals are transmitted away from the switch and onto a public or private network, multiplexed
communication becomes an option. Multiplexed communication results from the interleaving of signals
from multiple circuits into a single communications path. For transmissions with the same destination, it is
an economic alternative to using multiple single-trunk transmission paths.
TYPES OF MULTIPLEXING
Three types of multiplexing are used in switch communications: frequency-division multiplexing, time-
division multiplexing, and statistical multiplexing.
Frequency-Division Multiplexing
Frequency-division multiplexing provides a number of simultaneous channels over single analog medium
(twisted pair, coax, microwave, and so on) by using a different frequency band for the transmission of each
channel. Each channel provides a discrete data or conversation path.
Frequency-division multiplexing is used only for public network transmission facilities. The analog trunk
groups attached to private communication system switches — like the System 75, System 85, and DEFINITY
Generic 1 and Generic 2 communications systems — are not multiplexed.
Time-Division Multiplexing
In time-division multiplexing, a single transmission path is divided into several different communications
channels. The channels are assigned in units called time slots.
125 µSECONDS 125 µSECONDS
MY TIME SLOT
YOUR TIME SLOT
Figure 1-4. Time Slot
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