Digital Equipment DECbridge 500 Series Instruction sheet

Order Number: EK-DEFEB-PS-002
DECbridge500/600 Series
Problem Solving

1
NOTICE – Class A Computing Device:
Thisequipmentgenerates,uses,andmayemitradiofrequencyenergy. Theequipmenthas
been type tested and found to comply with the limits for a Class A computing device
pursuantto Subpart J of Part 15 of FCC Rules, which are designed to provide reasonable
protection against such radio frequency interference when operated in a commercial
environment.Operationofthisequipmentin aresidentialareamay causeinterference; in
which case, measures taken to correct the interference are at the user’s expense.
CAUTION
The people who install the cabling system described in this guide should be familiar with
local building codes, fire codes, and any other applicable codes or regulations. The
manufacturers or their distributors and agents will not be responsible for damage due to
improperly installed cabling, neglect, misuse, or improper connection of devices to the
cabling system.
NOTICE – Class 1 Laser Device:
The lasers in this equipment are Class 1 devices, compliant with CDRH Rules 21, CFR
Subchapter J, Part 1040.10, at date of manufacture. Class 1 laser devices are not
considered to be hazardous.

Order Number: EK-DEFEB-PS-002
DECbridge500/600 Series
Problem Solving
July 1991
This manual describes how to troubleshoot and service the
DECbridge 500/600 series. It is intended for qualified service
personnel who will be repairing the bridge to the
field-replaceable unit level.
Supersession/Update Information: This is a revised manual.

This manual was produced by Telecommunications and Networks Publications.
EK–DEFEB-PS-002
JULY 1991
Theinformationinthisdocumentissubjecttochangewithoutnoticeandshouldnotbeconstruedasa
commitmentbyDigitalEquipmentCorporation.DigitalEquipmentCorporation assumesnorespon-
sibility for any errors that may appear in this document.
Copyright 1991 by Digital Equipment Corporation
All Rights Reserved.
Printed in U.S.A.
The following are trademarks of Digital Equipment Corporation:
DEBET DECmcc ThinWire
DEC DECnet TURBOchannel
DEC FDDIcontroller DECstation ULTRIX
DECbridge DECUS UNIBUS
DECconcentrator DECwindows VAX
DECconnect DELNI VAXcluster
DECelms DESTA VAXstation
LAN Traffic Monitor
PDP VMS

iii
Contents
Safety
Preface
1 Introduction
1.1 General Description 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Problem Solving
2.1 Introduction 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Normal Power Up 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Self-Test Diagnostics (Overview) 2–4. . . . . . . . . . . . . . . . . . . . . . . .
2.4 Recommended Approach to Problem Solving 2–5. . . . . . . . . . . . . .
2.4.1 Problem-Solving Tools and Components 2–6. . . . . . . . . . . . . . . .
2.4.2 Running the Self-Test Diagnostics 2–6. . . . . . . . . . . . . . . . . . . . .
2.4.3 Visually Inspecting the Bridge 2–6. . . . . . . . . . . . . . . . . . . . . . . .
2.4.4 Interpreting the LED Indicators 2–9. . . . . . . . . . . . . . . . . . . . . . .
2.4.5 If the Problem Still Exists 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.6 Performing Loopback Testing 2–18. . . . . . . . . . . . . . . . . . . . . . . .
2.4.6.1 Preparing the Unit for Loopback Testing 2–18. . . . . . . . . . . . . .
2.4.6.2 Installing the FDDI Loopback Connector(s) 2–19. . . . . . . . . . .
2.4.6.3 Installing the NI Loopback Connector(s) 2–20. . . . . . . . . . . . . .
2.4.6.4 Running the Loopback Test and Observing the Results 2–22. . .
2.4.6.5 Returning to Normal Operation 2–22. . . . . . . . . . . . . . . . . . . . .
2.4.7 Measuring the FI Power 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iv
3 Removal and Replacement Procedures
3.1 Introduction 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 Preparing the Bridge for Servicing 3–3. . . . . . . . . . . . . . . . . . . . . . .
3.3 Removing and Replacing the FRUs 3–5. . . . . . . . . . . . . . . . . . . . . .
3.3.1 Tools Required 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 Removing and Replacing Logic Modules 3–5. . . . . . . . . . . . . . .
3.3.2.1 Removing Logic Modules 3–6. . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2.2 Replacing Logic Modules 3–7. . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3 Removing and Replacing the Card Cage 3–9. . . . . . . . . . . . . . . .
3.3.3.1 Removing the Card Cage 3–9. . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3.2 Replacing the Card Cage 3–10. . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4 Removing and Replacing the Power Supply 3–11. . . . . . . . . . . . .
3.3.4.1 Removing the Power Supply 3–11. . . . . . . . . . . . . . . . . . . . . . .
3.3.4.2 Replacing the Power Supply 3–12. . . . . . . . . . . . . . . . . . . . . . .
3.3.5 Removing and Replacing the Fan Assembly 3–13. . . . . . . . . . . . .
3.3.5.1 Removing the Fan Assembly 3–14. . . . . . . . . . . . . . . . . . . . . . .
3.3.5.2 Replacing the Fan Assembly 3–15. . . . . . . . . . . . . . . . . . . . . . .
3.3.6 Removing and Replacing the Backplane 3–15. . . . . . . . . . . . . . . .
3.3.6.1 Removing the Backplane 3–16. . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.6.2 Replacing the Backplane 3–16. . . . . . . . . . . . . . . . . . . . . . . . . .
4 Technical Information
4.1 Physical Description 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 DECbridge 500/600 Series Switches and Indicators 4–3. . . . . . . . .
4.2.1 Circuit Breaker 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2 Configuration Switches 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.3 Indicators 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 Block Diagram Description 4–9. . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1 AP2 (or AP) Module Description 4–10. . . . . . . . . . . . . . . . . . . . . .
4.3.2 QM Module Description 4–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3 FI Module Description 4–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.4 NI Module Description 4–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5 Power Supply 4–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

v
4.3.5.1 Power Supply Shutdown 4–12. . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5.2 Thermal Protection 4–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5.3 DC OK Output Signal 4–12. . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.6 Fan Assembly 4–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4 Product Specifications 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.1 Physical Specifications 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.2 Electrical Specifications 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.3 Environmental Specifications 4–15. . . . . . . . . . . . . . . . . . . . . . . . .
4.4.4 Cabling Specifications 4–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A Configuration Guidelines
A.1 General Guidelines A–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A.2 Bridge-to-FDDI Guidelines A–1. . . . . . . . . . . . . . . . . . . . . . . . . . . .
A.3 Bridge-to-802.3/Ethernet Guidelines A–2. . . . . . . . . . . . . . . . . . . . .
A.3.1 AUI Interface A–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A.3.2 ThinWire Interface A–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B FDDI Connection Information
B.1 FDDI Connection Rules B–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B.2 FDDI Connector Keying B–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C Related Documents
Index
Figures
1–1 DECbridge 500/600 Series in a Sample Configuration 1–1. . . . . . .
1–2 Typical DECbridge 500/600 Series Unit (I/O Panel) 1–3. . . . . . . . .
2–1 LED Indicators After Power Up 2–3. . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Visually Inspecting the Bridge 2–7. . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 Problem Solving a Power-Off Condition 2–14. . . . . . . . . . . . . . . . . .

vi
2–4 Problem Solving the FDDI Interface 2–15. . . . . . . . . . . . . . . . . . . . .
2–5 Installing the FDDI Loopback Connectors 2–19. . . . . . . . . . . . . . . . .
2–6 Installing the NI Loopback Connectors 2–21. . . . . . . . . . . . . . . . . . .
2–7 Measuring the FI Transmit Power (Multimode) 2–24. . . . . . . . . . . . .
2–8 Measuring the FI Receive Power (Multimode) 2–25. . . . . . . . . . . . .
3–1 DECbridge 500/600 Series Field-Replaceable Units 3–2. . . . . . . . .
3–2 Power Cord and Interface Cable Removal 3–4. . . . . . . . . . . . . . . . .
3–3 Logic Module Removal and Replacement 3–7. . . . . . . . . . . . . . . . .
3–4 Card Cage Removal and Replacement 3–10. . . . . . . . . . . . . . . . . . . .
3–5 Power Supply Removal and Replacement 3–12. . . . . . . . . . . . . . . . .
3–6 Fan Assembly Removal and Replacement 3–14. . . . . . . . . . . . . . . . .
3–7 Backplane Removal and Replacement 3–17. . . . . . . . . . . . . . . . . . . .
4–1 Typical DECbridge 500/600 Series Unit (I/O Panel) 4–1. . . . . . . . .
4–2 Switches and Indicators 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3 Simplified Block Diagram 4–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B–1 FDDI Connection Rules Matrix B–1. . . . . . . . . . . . . . . . . . . . . . . . .
B–2 FDDI Connector Keying B–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables
1–1 DECbridge 500/600 Series Units 1–2. . . . . . . . . . . . . . . . . . . . . . . .
1–2 Logic Modules used in the DECbridge 500/600 Series 1–4. . . . . . .
2–1 Problem Solving Via the LEDs 2–9. . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 FDDI Transmit and Receive Power Calculation 2–26. . . . . . . . . . . . .
3–1 Field-Replaceable Units 3–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–1 Configuration Switches 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–2 LED Indicators 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3 Physical Specifications 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–4 Electrical Specifications 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–5 Environmental Specifications 4–15. . . . . . . . . . . . . . . . . . . . . . . . . . .
4–6 Cable Specifications 4–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii
Safety !
Any warning or caution that appears in this manual is defined as follows:
Warning Contains information to prevent personal injury.
Caution Contains information to prevent damage to equipment.
Vorsicht Enthält Informationen, die beachtet werden müssen, um
den Benutzer vor Schaden zu bewahren.
Achtung Enthält Informationen, die beachtet werden müssen, um
die Geräte vor Schaden zu bewahren.
Danger Signale les informations destinées à prévenir les accidents
corporels.
Attention Signalelesinformationsdestinéesàprévenirla détérioration
du matériel.
Aviso Contiene información para evitar daños personales.
Precaucion Contiene información para evitar daños al equipo.

viii
Thewarningsandcautionsthatmustbeobservedfor thehardwaredescribedinthismanu-
al are listed below in English, German, French, and Spanish. The pages on which these
safety messages appear are also listed.
WARNING !To remove power from the unit, disconnect the power cord. Do not
applypowertotheunitunlessthecardcageassemblyisfullyinserted
in the bridge enclosure.
VORSICHT Schließen Sie das Gerät nicht an das Stromnetz an, solange das
Kartenmagazin nicht vollständig in das Gehäuse eingeschoben ist.
Ein Netzschalter ist nicht vorhanden! Um die Stromzufuhr zu un-
terbrechen, müssen Sie das Netzkabel aus der Steckdose ziehen.
DANGER Avant de mettre l’appareil sous tension, assurez-vous que le pan-
ier est complètement enfoncé dans le boîtier. Pour mettre l’ap-
pareil hors tension, débranchez le cordon d’alimentation.
AVISO No permita que llegue suministro eléctrico a la unidad, a menos
que el módulo de ensamblamiento de tarjetas esté completa-
mente insertado en la carcasa del puente. Para ello, desconecte el
cablede alimentación.
WARNING !Asafety earth ground wire has been incorporated into this product
through the plug cap of the ac power cord. For continued protection
againsttheriskofelectricalshock,thisproductmustbeconnectedto
athree-wire wall receptacle that has its grounding terminal reliably
connected to the building’s safety earth ground.
VORSICHT Das Stromkabel in diesem Gerät ist mit einem Schutzleiter verse-
hen. Um optimale Sicherheit zu gewährleisten, dürfen Sie es nur an
eineordnungsgemäß geerdete Schuko-Steckdose anschließen.
DANGER Cet équipement est mis à la terre au moyen du fil de terre du cor-
don d’alimentation secteur. Afin d’assurer une protection efficace
contretoutrisqued’électrocution,cetéquipementdoitêtreraccordé
à une prise secteur équipée d’un contact de mise à la terre
effectivement relié à la terre secteur du bâtiment.
AVISO Este producto incorpora un cable de tierra de seguridad mediante
el enchufe trifásico del cable de alimentación. Para evitar el riesgo
de descargas eléctricas, este producto debe estar conectado a un
receptáculotrifásico de pared que tenga su terminal de tierra debi-
damente conectado a la toma de tierra de seguridad del edificio.

ix
WARNING !Lethalexposedvoltagesexistinthepowersupply.Therefore,always
disconnect the ac power cord before removing or replacing any
FRUs.Do not apply power to the bridge unlessthecardcageisfully
inserted in the bridge enclosure. Only qualified service engineers
should perform any FRU removal and replacement procedures.
(Pages 3-1, 3-5, 3-11, 3-13, 3-15)
VORSICHT Die Spannung im Netzteil ist lebensgefährlich. Ziehen Sie immer
zuerst das Netzkabel aus der Wandsteckdose, wenn Sie FRUs ent-
fernen oder austauschen müssen. Schließen Sie das Gerät nicht an
das Stromnetz an, solange das Kartenmagazin nicht vollständig in
das Gehäuse eingeschoben ist. FRUs dürfen nur von qualifiziertem
Wartungspersonal entfernt oder ausgetauscht werden.
DANGER Le module d’alimentation comporte des connexions non isolées
soumises à des tensions dangereuses. Afin d’éviter tout risque
d’électrocution, prenez soin de débrancher le cordon d’alimenta-
tion avant toute intervention sur les composants internes de l’ap-
pareil. Avant de mettre l’appareil sous tension, assurez-vous que
le panier est complètement enfoncé dans le boîtier. Seuls les tech-
niciens de maintenance qualifiés sont habilités à effectuer les
opérations de dépose et de pose des unités remplaçables.
AVISO Debido a la existencia de alta tensión en el suministro eléctrico,
desconecte siempre el cable de alimentación retirando o reempla-
zando los FRU. Corte la alimentación eléctrica que llega al puente,
amenos que el módulo de tarjetas esté completamente insertado en
la carcasa del puente. Los procedimientos deretiraday sustitución
de los FRU debe llevarlos a cabo únicamente personal altamente
cualificado.
WARNING !Somecountries requirethatonlyauthorizedpersonnelbeallowedto
connect and disconnect power to the unit. (Page 3–1)
VORSICHT In einigen Ländern dürfen Elektrogeräte nur von entprechend
ausgebildetem Personal, beispielsweise Elektrikern, installiert
werden. Prüfen Sie, ob das in Ihrem Land zutrifft.
DANGER Assurez-vous que la législation vous autorise bien à effectuer les
branchements sur le secteur.
AVISO Algunos países requieren que sólo sea personal autorizado quien
conecteodesconectelaalimentacióneléctricaquellega a la unidad.

x
WARNING !Some fiber optic equipment can emit laser light that can injure your
eyes. Never look into an optical fiber, connector, or connector port.
(Page 3-4)
VORSICHT Schauen Sie niemals direkt in ein Glasfaserkabel oder einen Glas-
faseranschluß. DieLaserstrahleninfaseroptischenGeräten können
Augenverletzungen verursachen.
DANGER Certains équipements utilisant les fibres optiques peuvent émettre
des rayonnement laser dangereux pour les yeux. Ne vous avisez
jamais de regarder par l’extrémité d’une fibre optique ou dans
l’ouverture d’un connecteur. Considérez toujours que le câble est
relié à une source lumineuse.
AVISO Algunos equipos de fibra óptica emiten radiaciones láser que pue-
den dañar la vista. Nunca mire directamente a un conector o puerta
de conector de fibraóptica.
CAUTION !Modules in the bridge can be damaged by electrostatic discharges
(ESD). When working inside the unit, always use a grounded
wrist strap (ESD strap) and a grounded work surface. A wrist
strap, ground wire, and table pad are included in the field service
kit (P/N 29-11762-00). (Page 3-5)
ACHTUNG Die Module können durch elektrostatische Entladungen
beschädigtwerden. Benutzen Sie immer eine antistatische Ge-
lenkmanschette und eine geerdete Arbeitsunterlage, wenn Sie
am offenen Gerät arbeiten. Der Antistatikkit für das Wartung-
spersonal enthält eine antistatische Gelenkmanschette, Schutz-
leiterdraht und eine Antistatikmatte. Ein Antistatikkit ist bei
DECdirekt unter der Bestellnummer 29-11762-00 erhältlich.
ATTENTION Les charges excessives d’électricité statique peuvent endommag-
er les modules et les composants électroniques. Lors de la ma-
nipulation des modules et des composants internes, utilisez tou-
jours le bracelet de masse et le plan de travail antistatique
livrés avec le kit d’entretien (Réf. 29-11762-00).

xi
PRECAUCION Los módulos del puente pueden ser dañados por descargas elec-
troestáticas(ESD). Cuando se trabaje dentro de la unidad, use
una muñequera antiestática y una superficie de trabajo conectadas
ambas a tierra. En el juego de reparación (P/N 29-11762-00) se
incluye una muñequera antiestática, un cable de tierra y una
tabla.
CAUTION !These logic modules have components on both sides of the board.
Removing or inserting a module at a slight angle can damage it.
(Page 3-6)
ACHTUNG An beiden Seiten der Karte befinden sich logische Module.
Achten Sie darauf, daß Module absolut waagrecht entfernt oder
eingebaut werden müssen, da sonst die Karte beschädigt werden
kann.
ATTENTION Ces cartes comportent des composants sur les deux faces. Afin
d’éviter tout risque de détérioration, veillez à respecter l’al-
ignement lors des opérations de dépose et de repose.
PRECAUCION Estos módulos lógicos tienen componentes en ambas partes de
la placa. Si se retira o inserta un módulo en un ángulo indebido,
la placa puede quedar dañada.
CAUTION !Do not leave the card cage partially withdrawn for servicing. Re-
move it completely from the enclosure and set it down on a hori-
zontal surface. (Page 3-9)
ACHTUNG Wenn Sie Wartungsarbeiten durchführen, müssen Sie das Kar-
tenmagazin entfernen und auf eine ebene Fläche stellen. Es
genügt nicht, das Kartenmagazin teilweise herauszuziehen.
ATTENTION Lors des opérations d’entretien, ne laissez pas le panier à demi
sorti, mais retirez-le complètement du boîtier et posez-le sur un
plan de travail horizontal.
PRECAUCION No deje el módulo de tarjetas sacado sólo en parte. Retírelo
completamente de la carcasa y póngalo en una superficie hori-
zontal cuando vaya a trabajar con él.

xii
CAUTION !The card cage weighs approximately 11 kg (24 pounds). Support
it well and handle it carefully during removal to avoid dropping it.
(Page 3-9)
ACHTUNG Wenn Sie das Kartenmagazin entfernen, bedenken Sie, daß es
11 kg wiegt. Stützen Sie es mit einer Hand von unten ab, und
achten Sie darauf, daß es nicht auf den Boden fällt.
ATTENTION Le panier pèse environ 11 kg. Manipulez-le avec précaution
lors des opérations de dépose.
PRECAUCION El módulo de tarjetas pesa aproximadamente 11 kilos. Sujételo
con firmeza y manéjelo con cuidado durante su retirada, para
evitar su caída al suelo.

xiii
Preface
This manual describes how to troubleshoot and service the DECbridge 500/600 se-
riesofbridges.Information includes aproductoverview and listofthevarious mod-
els,problem-solvingmethods, removalandreplacement procedures, andguidelines
for configuring the units.
Intended Audience
This manual is intended primarily for qualified service personnel who will be re-
pairing the bridge to the field-replaceable unit level. The manual also contains gen-
eral information about the DECbridge 500/600 series that can be useful to Digital
Equipment Corporation training, services, and manufacturing personnel, as well as
system/network managers.
All procedures that deal with opening the unit for any reason are intended solely for
servicepersonnelwhohavebeentrainedtoperformproductmaintenanceandrepair.
KnowledgeofFiberDistributedDataInterface(FDDI)andIEEE802.3/Ethernetisa
prerequisite for using this manual effectively.
Document Structure
This document has four chapters and three appendixes, as follows:
Chapter 1 Briefly introduces the various models of the DECbridge 500/600 se-
ries and compares their similarities and differences.
Chapter 2 Presents an approach to solving problems with the bridge. This in-
cludes a description of a normal power-up sequence, an overview of
the self-test diagnostics, troubleshooting charts, and procedures for
performing loopback tests.

xiv
Chapter 3 Describes how to remove and replace all field-replaceable units
(FRUs).
Chapter 4 ContainstechnicalinformationabouttheDECbridge500/600series.
Includes a description of the product; a list of major assemblies,
switches,and indicators;andasummaryofthebridgespecifications.
Appendix A Presents configuration guidelines for connecting the bridge to an
FDDI and an IEEE 802.3/Ethernet network.
Appendix B Describes the FDDI connection rules and the keying of FDDI con-
nectors.
Appendix C Containsa list of related documents that can be ordered from Digital
Equipment Corporation.

1–1
1
Introduction
1.1 General Description
TheDECbridge500/600seriesunits (showninFigure1–1)providetheinterconnec-
tionbetweena100-Mb/s Fiber Distributed DataInterface(FDDI)networkandup to
three 10-Mb/s IEEE 802.3/Ethernet network segments.
Figure 1–1: DECbridge 500/600 Series in a Sample Configuration
FDDI network
IEEE 802.3/Ethernet
network segments
DECconcentrator 500 100 Mb/s
DECbridge 62x DAS
SAS
10 Mb/s
DECbridge 51x
LKG–5056–91I

1–2 DECbridge 500/600 Series Problem Solving
These bridges are store-and-forward devices. That is, they receive and store packets
fromtheFDDIringandIEEE802.3/Ethernetnetworksegments,thenselectivelyfil-
ter (discard) the packets or forward them to the appropriate network.
As shown in Table 1–1, various network interfaces are available, depending on the
particular bridge model.
Table 1–1: DECbridge 500/600 Series Units
Model Option # No. of FDDI FDDI Optics
NI Ports Connection
500 DEFEB-AA/AB 1 SAS Multimode
510 DEFEB-AC/AD 1 SAS Multimode
518 DEFEB-AS/AT 1 SAS Single-mode
520 DEFEB-DA/DB 1 DAS Multimode (Port A/Port B)
524 DEFEB-DP/DQ 1 DAS Single-mode (Port A) / Multimode (Port B)
526 DEFEB-DM/DN 1 DAS Multimode (Port A) / Single-mode (Port B)
528 DEFEB-DS/DT 1 DAS Single-mode (Port A/Port B)
600 DEFEB-UC/UD 3 None Null
610 DEFEB-TA/TB 3 SAS Multimode
618 DEFEB-TS/TT 3 SAS Single-mode
620 DEFEB-LA/LB 3 DAS Multimode
624 DEFEB-LP/LQ 3 DAS Single-mode (Port A) / Multimode (Port B)
626 DEFEB-LM/LN 3 DAS Multimode (Port A) / Single-mode (Port B)
628 DEFEB-LS/LT 3 DAS Single-mode
FDDI Interfaces:
•A single attachment station (SAS) with one connector or a dual attachment
station (DAS) with two connectors. Each connector can be either multimode
or single-mode. The DAS multimode versions also have a relay driver to con-
trol an optional optical bypass relay.
•A null interface that provides no connection to the FDDI network.

Introduction 1–3
IEEE 802.3/Ethernet (NI) Interfaces:
•Asingle AUI/ThinWire (switch-selectable) port
•Three independent AUI ports
Figure 1–2 shows the major assemblies and user interfaces in a typical DECbridge
500/600seriesunit.Notethatthenumberandtypeofinterfaceconnectorsmaydiffer
depending on the model:
•DAS bridges have two FDDI connectors, SAS bridges have one FDDI con-
nector, and the DECbridge 600 model has no FDDI connector.
•All DECbridge 500 series models have an AUI connector and a ThinWire
connector (switch-selectable) for the single IEEE 802.3/Ethernet interface.
The DECbridge 600 series models all have three AUI connectors.
NOTE
The DECbridge 510 shown in Figure 1–2is representa-
tive of the DECbridge 500/600 series. However, the
number and type of interface connectors differs in the
various models, as described in the previous text.
Figure 1–2: Typical DECbridge 500/600 Series Unit (I/O Panel)
Circuit breaker
AC power
connector
Module
I.D. Configuration
ThinWire
connector
(Port 2) Address
label
AUI
connector
(Port 2)
FDDI
connector
(Port 1)
Serial
number
LKG-5112–91I
AP
NI
FI
QM
Model number
switches

1–4 DECbridge 500/600 Series Problem Solving
All DECbridge 500/600 series units contain four logic modules:
•AP or AP2 (Application Processor) module
•NI or NI(3) (Network Interface) module
•FI (Fiber Interface) module with various types of interfaces
•QM (Queue Manager) module
Table 1–2 shows the four logic modules contained in each bridge model.
NOTE
In this manual, the terms AP and NI are used as general
references to the Application Processor and Network
Interface modules. The terms AP2 and NI(3) are used
only when referring specifically to those two modules.
Table 1–2: Logic Modules used in the DECbridge 500/600 Series
Model AP Module NI Module QM Module FI Module
500 AP NI QM FI (SAS, MM)
510 AP2 NI QM FI (SAS, MM)
518 AP2 NI QM FI (SAS, SM)
520 AP2 NI QM FI (DAS, MM)
524 AP2 NI QM FI (DAS, SM-A, MM-B)
526 AP2 NI QM FI (DAS, MM-A, SM-B)
528 AP2 NI QM FI (DAS, SM)
600 AP2 NI(3) QM FI (Null)
610 AP2 NI(3) QM FI (SAS, MM)
618 AP2 NI(3) QM FI (SAS, SM)
620 AP2 NI(3) QM FI (DAS, MM)
624 AP2 NI(3) QM FI (DAS, SM-A, MM-B)
626 AP2 NI(3) QM FI (DAS, MM-A, SM-B)
628 AP2 NI(3) QM FI (DAS, SM)
Legend: SAS – Single attachment station
DAS – Dual attachment station
MM – Multimode
SM – Single-mode
Aand B – DAS interface connectors