Digital Equipment MUXserver 100 User manual

EK-DSRZA-RM-~)02
.••.........•........•................ -
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• • • • • • • • • • • • •• • • • • • • • • • • • • • • • • • • • • • • • •
MUXserve'r 100
Network
ReferenC'9 Manual·

MUXserver 100 Network
Reference Manual

© Digital Equipment Corporation 1986
All Rights Reserved
2nd Edition, November 1986
The information in this document
is subject to change without notice and should not be
construed as a commitment by Digital Equipment Corporation. Digital Equipment
Corporation assumes no responsibility
for any errors that may appear in this document.
Printed in U.S.A.
This document was set on a DIGITAL DEC set Integrated Publishing System.
The following are trademarks of Digital Equipment Corporation:
~DmDDmDTM
DECUS
RSTS
DECwriter
RSX
DEC
DIBOL
Scholar
DECmate
MASSBUS
ULTRIX
DECmux
MUXserver
UNIBUS
DECset
PDP
VAX
DECsystem-l0
P/OS
VMS
DECSYSTEM-20
Professional VT
Rainbow Work Processor

CONTENTS
Page
CHAPTER 1 THE MUXserver 100 I~NVIRONMENT
1.1 GENERAL INFORMATION .................... 1-1
1.2 LOCAL AREA NETWORKS AND THE LAT ARCHITECTURE . 1-3
1.3 WIDE AREA NETWORKS AND STATISTICAL
MULTIPLEXERS ..... .1-3
1.3.1
1.3.2
1.3.3
1.3.4
1.4
1.4.1
1.4.2
1.5
1.6
1.6.1
1.6.2
Statistical Multiplexing. .
Composite Links . . . . . .
Multiplexer Configuration
Asynchronous
Ports -Mapping ..
THE SERVER MANAGER ENVIRONMENT ..
The Supervisor Ports . . . . . . . . . . . .
Privileged
and Non-Privileged Commands
DATABASES ON THE MUXserver 100 .....
THE TERMINAL USER ENVIRONMENT
Local Mode ................ .
Service Mode . . . . . . . . . . . . . . .
... 1-4
· .1-5
· .1-5
.1-8
· .1-8
· .1-9
.... 1-10
1-11
1-12
· 1-12
· 1-12
CHAPTER 2 SETTING UP THE MUXserver 100 AND ITS TERMINALS
2.1 ENTERING PRIVILEGED STATUS ........... : ... 2-2
2.2
SETTING UP THE PRIVILEGED PASSWORD ......... 2-2
2.2.1
Setting Up the Privileged Password On the MUXserver 100 ... 2-2
2.2.2
Setting Up the Password On the DECmux II .......... 2-3
CONTENTS 1

2.3
2.4
2.4.1
2.4.2
2.4,3
2.5
2.5.1
2.5.1.1
2.5.2
2.6
2.7
2.7.1
2.7.2
2.7.3
2.7.4
2.7.5
2.8
2.9
2.9.1
2.9.2
2.10
SETTING UP THE LOGIN PASSWORD ...... .
SETTING UP THE SERVER CHARACTERISTICS
Network Operation Characteristics ..
Loading and Dumping Characteristics ...... .
Server Administration Characteristics . . . . . . .
SETTING UP THE COMPOSITE LINK PARAMETERS.
Setting Link Speed and Line Type on the MUXserver 100 .
Switch Selection of RS-232 or RS-422 Long Line Drive .
Setting Link Speed and Line Type on the DECmux II Unit
SETTING UP THE NETWORK MAP . . . . . . .
SETTING UP THE PORT CHARACTERISTICS
Session Control Characteristics
Port Data Characteristics ..
Flow Control Characteristics . .
Switch Characteristics . . . . .
Port Administration Characteristics
MUXserver 100 INITIALIZATION ..
SETTING CHARACTERISTICS TO FACTORY
SPECIFICATIONS . . . . . . . . . . . . . . . .
Resetting the MUXserver 100 to Factory Settings.
Page
· .2-8
· .2-8
· . 2-10
2-11
· 2-12
2-13
2-13
2-16
2-18
· 2-20
2-22
· 2-26
2-29
· 2-30
2-32
2-33
· 2-35
2-37
2-37
· 2-38
Resetting the DECmux II Unit to Factory Settings
SETTING UP PRINTERS . . . . . . . . . . . . . . ... 2-39
CHAPTER 3 MANAGING AND MONITORING
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.4.1
3.1.4.2
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
MANAGING
THE MUXserver 100 ..
Security Management ....... .
Service Mode Management . . . . . .
Communication with Terminal
Users .
Remote Management of the MUXserver 100
(By Means of the Ethernet) . . . . . . . . . .
Setting Up a Remote Console . . . . . . .
· .3-1
· .3-2
· .. 3-3
· .. 3-3
· .. 3-4
· .3-6
Using MUXserver 100 Commands on a Remote Console
MONITORING THE MUXserver 100 (By Means of the Network
Remote Console or Supervisor Port Terminal)
· .3-7
.3-8
Show Counters
Show Nodes.
Show Server
Show Port ..
Show Users.
· .3-9
· . 3-10
· 3-10
· . 3-11
· 3-11
2 CONTENTS

3.2.6
3.3
3.3.1
3.3.2
3.3.2.1
3.3.2.2
Show Queue ....................... .
MONITORING THE REMOTE DECmux II NETWORK
Show Communications
Communications
Status
Map ..... .
Page
· 3-11
· 3-12
· 3-12
.. 3-13
3-13
3-13
CHAPTER 4 MUXserver 100 TROUB]~ESHOOTING
4.1
4.2
4.2.1
4.2.2
4.2.2.1
4.2.2.2
4.2.2.3
4.2.2.4
4.2.3
4.2.4
4.2.4.1
4.2.4.2
4.2.5
4.2.6
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.5.1
4.3.5.2
4.4
4.4.1
4.4.2
4.4.3
4.4.4
4.5
4.5.1
WHAT TO DO
FIRST .................... .4-6
PROBLEMS AFFECTING ALL PORTS . . . . 4-7
Server Green Light Off . . . . . . . . . . .4-8
Error Messages on the Supervisor Port Terminal ........ 4-9
nnn1 - Server Paranleters Checksum Error . . . .. 4-9
nn1n -Hardware Revision Level Checksum Error . . . 4-10
n1nn - Ethernet Loopback Error . . . . . . . . . . . . 4-10
1nnn - Ethernet Heartbeat Error. . ....... 4-12
No Supervisor
Port Messages ... . 4-12
Down-line Loading Problelns . . . . . . 4-13
Down-line Load
Starts, Then Fails ....... 4-13
Down-line Load Does Not
Start . 4-14
Message Number 913 Appears . . . .
......... 4-17
Terminal
Port or Terminal Hardware Problems ..... . 4-19
PROBLEMS INVOLVING THE COMPOSITE LINKS . 4-20
Check
the GREEN Light of the DECmux II . . . . .. .. 4-22
Green
LED on Steady, DSR Light Off (RS-232 Lines ONLY)
(This Applies to Both the lVlUXserver 100 and the
DECmux II). . . . . . . . . . . . . . . . . . . . . . .. . 4-22
All Indicators OK -Check Composite Link
Parameters .... 4-23
Error Message -'Synchronous Port Connection Error' . . 4-23
Diagnostic
Tests . . . . . . . . . . . . . . . . . . . . 4-24
Diagnostic
Tests with the Composite Link Installed ..
· 4-24
Diagnostic
Tests Using LOOPBACK Connectors
PROBLEMS AFFECTING INDIVIDUAL PORTS.
Terminal Display is W ronl~ . . . . . . . . . .
Error Messages Displayed, Green Light ON . .
PC File Transfer Fails ............ .
A Line
Printer Fails at a Remote Access Port
.. 4·26
· 4-28
...... 4-28
· 4-33
· 4·34
· 4-34
PROBLEMS INVOLVING SERVICE NODES.
. . . . .. . 4-36
Message Timing Problem . . . . . . . . . . . .
.... 4-36
CONTENTS 3

4.5.2
4.5.3
4.5.4
4.5.5
4.6
4.7
4.7.1
4.7.2
4.7.3
Page
LAT Protocol Errors . . . . . . . . ....... 4-37
Group Codes
Mismatch. . . . . . . . . 4-38
Service Node Software Not Running . . . . . 4-39
Service Node Not Available. . . . . . . ...... 4-39
PROBLEMS INVOLVING THE ETHERNET .......... 4-40
DIGITAL SERVICE ...... ,.......... . 4-40
Before you Contact DIGITAL .....
Repackaging the Server for Shipment
Forwarding Up-line Dump Data ....
· 4-41
· 4-41
· 4-41
CHAPTER 5 MUXserver 100 COMMAND DESCRIPTIONS
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
5.15
5.16
5.17
5.18
5.19
5.20
5.21
5.22
5.23
5.24
5.25
5.26
5.27
5.28
4
BACKWARDS ... . ·
.5-2
BROADCAST .... . .
... 5-3
COMMUNICATIONS ..... . ·
.5-4
CONNECT ........... . .
.... 5-5
CONNECT (Part of the Communications Sub-directory) .... 5-7
DEFINE SET -PORT ... . . . . . . . . . . . . . . 5-9
DEFINE SET - SERVER. . . . . . . . . . . . . . . . . . 5-17
DISCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
DISCONNECT (Part of the Communications Sub-directory). . 5-25
FORWARDS . . . . . . . . 5-25
HELP. . . .. ........... . ......... 5-26
INITIALIZE. . . . . . . . . . . . . . . . 5-27
LOCK. . . . .................. 5-29
LOGOUT . . . . . . . . . . . . . . . 5-30
LOOP. . . . . . . . . . . . . . . . . . . . . .. . 5-30
MAP. . . . . . . . . . . . . . . . . .. 5-32
MAPHELP (Part of the Communications Sub-directory) .. 5-38
MONITOR COMMUNICATIONS .. 5-35
MONITOR COUNTERS . . . . . . . . . 5-36
MONITOR QUEUE. . . . . . . . . . . . . . . . . . . . 5-36
REMOVE
QUEUE . . . . . . . . . . . . . . . . . . .. .. 5-37
RESTART (Part of the Communications Sub-directory) . . 5-38
RESUME . . . . . . . . . . . . . . . . . . . . . . . . . 5-39
SAVE (Part of the Communications Sub-directory) . . . . . 5-40
SET NOPRIVILEGED . . . . . . . . 5-40
SET PRIVILEGED . . . . . . . . 5-41
SET SESSION . . . . . . . . . . . . . . . . . 5-42
SHOW COMMUNICATIONS . . . . . . . . . . . . 5-43
CONTENTS

5.29
5.30
5.31
5.32
5.33
5.34
5.35
5.36
5.37
5.38
5.39
5.40
5.41
5.42
5.43
SHOW COUNTERS
SHOWNODES ..
SHOWPORTS ..
SHOW QUEUE .
SHOW SERVER
SHOW SERVICES
SHOW
SESSIONS
SHOWUSERS ..
SHOW (Part of the Communications Sub-directory)
STATUS (Part of the Communications Sub-directory)
START TEST ..................... .
STOP TEST PORT . . . . . . . . . . . . . . . . . .
SYSTEM (Part of the ComlTlUnications Sub-directory)
TEST (Part of the Communications Sub-directory) . .
ZERO COUNTERS . . . . . . . . . . . . . . . . . .
Page
5-44
· 5-48
5-51
· 5-52
5-53
· 5-56
5-59
· 5-60
· 5-61
... 5-62
· 5-62
.. 5-64
5-64
... 5-66
· 5-68
CHAPTER 6 DECmux II OPERATION
6.1
6.1.1
6.1.1.1
6.1.1.2
6.1.2
6.2
6.2.1
6.2.2
6.2.3
6.2.3.1
6.2.4
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.3.6.1
6.3.6.2
6.3.6.3
6.3.7
CONTROLS AND INDICA~rORS
Indicators . . . . . . . . . .
Start-Up Indicator . . . . .
Data
Set Ready Indicators .
Controls
......... .
OPERATION ........ .
Starting Your DECmux IJ[
Master/Slave . . . . . . . .
Multiplexer Network . . .
Remote Supervisor Commands
DECmux II Off-Line
Diag~nostic ..
· .6-1
· .. 6-1
· .6-1
· .6-2
.6-2
.6-4
.6-4
· .. 6-4
.
........... 6-5
.......... 6-5
.6-5
DECmux II COMMAND PItOCESSOR SUMMARY ·
.6-6
.6-6
CONNECT Command .. .....
COpy Command . . . . .
DISCONNECT Command
EXIT Command
HELP Command . . . . .
MAP Command. . . . . . .
Link Selection (Only possible on
the MASTER)
Port Selection ....... .
Exiting
the MAP Conllnand
MAP HELP Command . . . . .
· .6-7
· .. 6-8
.6-8
· .. 6-9
... 6-10
· . 6-11
· . 6-12
· . 6-12
· . 6-13
CONTENTS 5

6.3.8
6.3.9
6.3.10
6.3.11
6.3.12
6.3.13
6.3.14
6.3.15
6.3.16
6.4
PASSWORD Command
PORT Command . . .
RESTART Command ..
SAVE Command . .
SHOW Command. .
STATUS Command
SYSTEM Command
HALT Command . .
TEST Command ..
ASYNCHRONOUS PORT MODEM CONTROL.
Page
6-14
· 6-15
· 6-18
6-18
6-19
.. 6-20
... 6-21
6-23
6-23
6-24
CHAPTER 7 DIAGNOSTICS
7.1
7.1.1
7.1.1.1
7.1.1.2
7.1.1.3
7.1.2
7.1.2.1
7.1.2.2
7.1.3
7.1.3.1
7.1.3.2
7.1.3.3
7.2
7.2.1
7.2.2
7.2.2.1
7.2.2.2
7.2.2.3
7.2.2.4
7.2.2.5
7.2.2.6
7.2.2.7
7.2.2.8
DIAGNOSTIC MODULES . . . . . . . . . . . . 7-1
Module A - Server Memory and Tinler Tests . . 7-2
Module B - UART Transmit/Receive
Test .7-2
Module C - Network Interface (NI) Transmit/Receive Tests . . 7-3
Module D - Hardware Exerciser
Error Types . .
Soft Errors .
Hard Errors
ODT ..... .
Examine (E) Command.
Examine Byte (EB) Command .
Register Dunlp
(R) Conlmand .....
TESTING DECmux II . . . . . . .
TEST Command ....... .
DECmux II Diagnostic Summary
Offline Test 1 - Basic Option Test
Offline Test 2 - Asynchronous Port External Test
Offline Test 3 - Asynchronous Internal Logic Test ..
Offline Test 4 - Composite External Port Test . .
Offline Test 5 - Composite Internal Logic Test .
Offline
Test 6 - Broadcast Test .....
Offline Test 7 - Echo Test . . . . . . .
Offline
Test 8 - Modem Control Test .
.7-4
.7-4
· .7-4
.7-7
7-10
· 7-11
· 7-12
· 7-13
7-13
· 7-15
7-16
· 7-16
· 7-17
· 7-19
7-19
· 7-21
7-21
.. 7-23
7-23
6 CONTENTS

CHAPTER 8 SPECIFICATIONS
8.1
8.1.1
8.1.2
8.1.3
8.2
8.2.1
8.2.2
8.2.3
8.2.4
DSRZA-XX SYSTEM UNIT
Composite Port Interface.
Supervisor Port .... , ..
Ethernet Interface .. , ..
DECmux II SPECIFICATION
DFMZA-XX System Unit
Composite
Port Interface.
Asynchronous Ports
Supervisor Port . . . . . .
APPENDIX A STATUS AND ERROR MESSAGES FOR THE
MUXserver 100
Page
.8-1
· .8-2
.8-2
.8-3
.8-3
· .8-4
· .8-5
.8-5
.8-6
A.1 CLASSES AND FORMATS OF MESSAGES ........... A-1
A.2 MESSAGE LISTINGS AND EXPLANATIONS .......... A-3
A.2.1 Informational Messages (Message Codes 000-099 and 500-599) .A-3
A.2.2 Warning Messages (Message Codes 100-199 and 600-699)
.. .A-5
A.2.3 Connection
Error Messages (Message Codes 200-299) .A-6
A.2.4 User
Error Messages (Message Codes 700-799) . . . .A-8
A.2.5 Supervisor
Port Messages (Message Codes 900-999) .. .. A-14
APPENDIX B COMMUNICATIONS PROCESSOR MESSAGES FOR
MUXserver 100 AND DECmux II
B.1
B.2
B.2.1
B.2.2
B.2.3
B.2.4
COMMUNICATIONS PROCESSOR MESSAGES
TEST MODE MESSAGES ............ .
Multi-Protocol Serial Controller Chip (MPSCC)
Test
Error Messages . . . . . . . . . . . . . . . . . . .
Other Test Program and Hardware Related Errors.
Modem Line Test . . . . . . . . . .. .....
Asynchronous Ports Error Messages.
GLOSSARY
.B-1
· .B-4
· .B-4
· .B-6
· .B-7
.B-7
CONTENTS 7

1-1
1-2
1-3
1-4
2-1
2-2
2-3
2-4
3-1
4-1
4-2
4-3
6-1
7-1
7-2a
7-2b
7-3
7-4
7-5a
7-5b
7-6
7-7
8
FIGURES
Local Area Network (LAN) ....... .
HDLC
Frame Format ......... .
Default Multiplexer Configuration
No.1.
Default Multiplexer Configuration No.2. .
Numbering
System for the First Default Multiplexer
· .1-2
· .1-4
.... 1-6
· . 1-7
Configuration .......................... . ·
.2-6
Numbering System for the Second Default Multiplexer
Configuration
...................... .
RS-232/RS-422 Switch Selection ............ .
DECmux II with Cover Removed Showing Location of J4 .
Server Manager's Remote Console on an Ethernet
Network Components .......... .
Breakdown of LAT Network
Components.
Diagnostic Test Loopback Points
DECmux II Indicators ..... .
.2-7
· 2-17
· 2-39
.3-5
. ..... 4-2
.4-4
· 4-25
.6-3
DECmux II Loopback Points ... . ....
Asynchronous Port External Test
Asynchronous Port External Test Display .
Asynchronous Internal Logic
Test .
.
..... 7-14
.. 7-18
Composite
External Port Test .....
Asynchronous Port Broadcast Test . . .
Asynchronous
Port Broadcast Message
Asynchronous
Port Echo Test . . . . . .
Composite and Asynchronous
Port Modem Control Test
CONTENTS
· 7-18
· 7-19
.
.. 7-20
· 7-22
.. 7-22
· 7-23
· 7-24

2-1
2-2
2-3
2-4
2-5
4-1
5-1
6-1
6-2
7-1
7-2
7-3
7-4
7-5
8-1
A-I
TABLES
Server Characteristics ..
. .. 2-9
Composite Port Parameters . . . . . . . . . . . . . . . . . . . .
Composite
Port Parameters
· 2-14
2-18
Terminal Characteristics ....
· 2-24
Setting Up Port Characteristics for a Printer . . . . . ·
2-40
Terminal Behavior and Possible Problems . . . . . . . . . . . . . · 4-29
5-65Composite Port Parameters . ,
Asynchronous Port Parameters
Composite Port Parameters . ,
Non-Fatal (Soft) Error Types "
Error Status Parameter Longword
Fatal (Hard) Error Types. . . " . . .
Fatal (Hard) Error Codes Written to EEPROM . . . . .
Basic Option Sub-Test . . . . ., . . . .. .....
Ethernet Characteristics . . ., . . . .
Classes of Status and Error Messages . .
· 6-16
6-21
... 7-5
· .7-6
· .7-8
· .7-9
· 7-17
.8-3
.A-2
CONTENTS 9

PREFACE
The MUXserver 100 Network Reference Manual presents information needed
to set up, manage, monitor, and troubleshoot the MUXserver 100 and remote
DECmux II. For information about routine operation of
the MUXserver 100
remote terminals, refer to the MUXserver 100 User's Pocket Guide.
This guide is intended for anyone who is responsible for maintaining and ma-
naging a MUXserver 100 Remote Terminal Server. In this guide,
that person
is
the server manager.
This guide is composed of
the following sections:
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
provides an overview of
the MUXserver 100 and of the server
managers environment.
provides in-depth information on using
the MUXserver 100
commands to set up the server, and the composite links and
remote ports of
the DECmux II units.
discusses
the MUXserver 100 commands you use to manage
and monitor
the serv,er, DECmux II units, and remote ports.
contains a troubleshooting guide for
the MUXserver 100,
DECmux II units, composite links and remote ports.
contains a complete alphabetical reference of
the MUXserver
100 commands.
contains a complete description of
the DECmux II commands.
PREFACE 1

Chapter 7
Chapter 8
Appendix A
Appendix B
outlines
the diagnostic tests available on the MUXserver 100
and the DECmux II unit.
contains
the specification for both the MUXserver 100 and the
DECmux II unit.
provides a listing and explanation of all MUXserver 100
status
and error messages except those relating to the communica-
tions processor (that is, those relating to
the composite commu-
nications links).
provides a listing and explanation of the
status and error mes-
sages for
the communications processor in the MUXserver 100
and the DECmux II unit.
RELATED MUXSERVER 100
REMOTE TERMINAL SERVER DOCUMENTS
• MUXserver 100 VMSIMicroVMS Software Installation Guide
Describes the installation and configuration of the server software or
VMS/MicroVMS systems.
• MUXserver 100 User's Pocket Guide
Summarizes the MUXserver 100 remote terminal user's environment.
• MUXserver 100 Network Installation Manual
Describes environmental requirements and installation for both the
MUXserver 100 and the DECmux II units.
• MUXserver 100 Network Identification Card
Contains identification information entered by the hardware installers,
system managers, and
the network manager.
• LAT Network Manager's Guide
Discusses the Local Area Transport (LAT) architecture, the LAT
Control Program (LATCP), and network troubleshooting.
2 PREFACE

CONVENTIONS USED IN 'THIS GUIDE
Convention
UPPERCASE
[]
{}
<KEY>
Meaning
Uppercase in comnlands and examples given indicates that
you should enter the characters as shown (enter either upper-
case or lowercase).
Square brackets indicate that the enclosed text is optional. If
there is more than one option, you can choose one and only
one of
the options. Do not type the brackets when you enter
the command.
Braces indicate
that the enclosed text is required and you
must choose one an.d only one of the options. Do not type
the braces when you enter the command.
Indicates
that you should press the specified. key. <CTRLI
x> indicates that you should press the <CTRL> key at the
same time as the <x> key, where x is a letter. Note that
unless otherwise specified, every command line is terminated
by pressing
the <RET> key.
All numbers are decimal unless otherwise noted. All Ethernet addresses are
given in hexadecimal.
NOTE
Generally you can abbreviate (!omnland keywords to the first three
characters or the number of characters that make the keyword
unique.
NOTES, CAUTIONS, AN[) WARNINGS
Where notes, cautions, and warnings are used in this document, they highlight
specific types of information as follows:
NOTE
[ CAU!I~~:]
WARNING I
Calls attention to information in text that may be of special
importance.
Calls attention to information in
text essential to avoiding
system or equipm.ent damage.
Calls attention to information in
text essential to the safety
of personnel.
PREFACE 3

FCC USER STATEMENT
NOTICE:
This equipment generates, uses, and may emit radio frequency energy. The
equipment has been type tested and found to comply with the limits for a Class
A computing device pursuant to Subpart J of Part 15 of FCC rules, which are
designed to provide reasonable protection against such radio frequency inter-
ference. Operation of this equipment in a residential area may cause inter-
ference in which case the user at his own expense will be required to take
whatever measures may be required to correct the interference.
4 PREFACE

CHAPTER 1
THE MUXserver 100 ENVIRONMENT
1.1 GENERAL INFORMATIION
The MUXserver 100 is a high perforrnance, low-cost remote terminal server for
use on
an Ethernet Local Area Network (LAN). It allows up to sixteen termi-
nals
to connect to computer systems on the Local Area Network. The terminals
are physically connected to two DECInux II units which may be
at separate
remote geographic locations. Each
DgCmux II unit communicates with a
MUXserver 100 by means of a statistically multiplexed synchronous link (re-
ferred
to as the COMPOSITE link) which is provided by either an RS-232
Synchronous Modem for large distances or RS-422 Long Line Drivers for local
links. Each remote terminal appears to have direct connection to
the computer
systems and resources available on
the Local Area Network. Remote users can
switch among several
data processing- tasks as quickly and conveniently as local
terminal users connected by means of a DECserver 100.
Figure 1-1 shows how the MUXserver 100 fits into a computer network called
a Local Area Network
(LAN). Local area networks serve relatively small areas;
ranging, for example, from a section of a building
to a college campus. Users
remote from
the LAN can now access all the LAN facilities.
CHAPTER 1 THE MUXserver 100 ENVIRONMENT 1

TRANSCEIVER
'ETHERNET CABLE
TERMINALS
TERMINALS
Figure 1-1 Local Area Network (LAN)
2 CHAPTER 1 THE MUXserver 100 ENVIRONMENT
TERMINALS
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