Section 6 NON-ISDN NETWORKS
100
First, A Glossary
Some terms you will need to navigate this section:
V.35.
A standard for interconnecting synchronous digital data paths. Like RS- 232, it
defines signals and (not officially) connectors and pin- outs so that equipment from
various manufacturers may talk with each other. The usual connector is a big boxy AMP
type which was chosen by AT&T decades ago. Most terminal equipment sold for the US
market supports the V.35 standard.
X.21.
A more modern standard, also for interconnecting synchronous digital data
paths. This standard specifies the much more reasonable DB- 15 connector.
Fortunately, it is possible to design a receiver which accepts both V.35 and X.21 signals.
This we have done with the Zephyr, allowing connection to both types just by changing
the interconnect cables. The X.21 standard is frequently seen in Europe.
Throughout this manual, we use the universal designation
“ V.35/X21” to refer to the Zephyr’s digital I/O port protocol.
CSU. Channel Service Unit. DSU. Data Service Unit
.
This is what the
interface between the Zephyr and digital channel is usually called. It converts the
signals from the telephone line to the required V.35 or X.21 standard and provides
dialing capability. (Some have keypads and LCD displays for this function; others rely
upon external computer control.) The designation CSU is most often used when
terminating Switched- 56 lines. Modular CSUs are also used within a
Channel Bank
to
break out the various paths. Originally the CSU and DSU were separate pieces of
equipment. Now they are nearly always one piece of gear variously referred to as a CSU,
DSU, CSU/DSU, or a DSU/CSU.
TA. Terminal Adapter
.
Performs same function as CSU. This terminology is most
commonly used with equipment applied to ISDN lines.
Throughout this manual, we use the universal designation “TA/CSU” to refer
generally to an external ISDN or Switched- 56 interface device.
CURIOSITY NOTE!
You might wonder why the much more common RS-232 is not
used. Answer: V.35 is synchronous, meaning that the bit clock
is transmitted between the two ends. Self-clocking standards,
like RS-232, require overhead start and stop bits, slowing and
chopping the bit flow. And, just as with audio, balanced
transmission is more reliable in a noisy environment, or in one
which has ground potentials at differing levels.
DEEP TECH NOTE!
The standard uses electrically balanced transmission for both
clock and data (but not for the special auxiliary signals, which
are identical to RS-232). The transmit voltage level is ± 5.5V,
but receivers must handle wider swings.
Summary of Contents for Zephyr
Page 13: ...Table of Contents 13 SECTION 1 QUICK RESULTS ...
Page 26: ...Section 2 INTRODUCTION 26 This page intentially left blank ...
Page 27: ...Section 2 INTRODUCTION 27 SECTION 2 INTRODUCTION ...
Page 38: ...Section 2 INTRODUCTION 38 This page intentionally left blank ...
Page 39: ...39 SECTION 3 ZEPHYR AT A GLANCE ...
Page 52: ...Section 4 INSTALLATION BASIC OPERATION 52 This page intentionally left blank ...
Page 53: ...Section 4 INSTALLATION BASIC OP 53 SECTION 4 INSTALLATION BASIC OPERATION ...
Page 84: ...Section 4 INSTALLATION BASIC OPERATION 84 ...
Page 85: ...Section 5 ISDN 85 SECTION 5 ISDN ...
Page 105: ...Section 6 NON ISDN NETWORKS 105 SECTION 7 AUDIO CODING ...
Page 118: ...Section 7 AUDIO CODING PRINCIPLES 118 This page intentionally left blank ...
Page 119: ...Section 8 DETAILED MENU REFERENCE 119 SECTION 8 DETAILED MENU REFERENCE ...
Page 157: ...Section 9 REMOTE CONTROL 157 SECTION 9 REMOTE CONTROL ...
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Page 177: ...Section 10 ADVANCED PROBLEM SOLVING 177 SECTION 10 ADVANCED PROBLEM SOLVING ...
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Page 197: ...Section 11 TECHNICAL INFORMATION 197 SECTION 11 DETAILED TECHNICAL INFORMATION ...
Page 219: ...Section 12 SCHEMATICS 219 SECTION 12 SCHEMATICS ...
Page 221: ...Section 13 MANUFACTURER S DATA SHEETS 221 SECTION 13 MANUFACTURER S DATA SHEETS ...
Page 223: ...Section 14 SPECIFICATIONS WARRANTY 223 SECTION 14 SPECIFICATIONS AND WARRANTY ...
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Page 229: ...Section 15 APPENDICES 229 SECTION 15 APPENDICES ...