Allied Telesy n International

Allied Telesy n International
Allied Telesyn
International
CentreCOM
Fiber Optic
Micro Repeaters
AT-MR116F
— | AT-MR117F
AT-MR118FT
— | па
AI-MR127F RS 201-13
AT-MRI28FT RS 201-173;
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ARENT.
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Electrical Safety and Installation
Requirements
>
> E
RADIATED ENERGY
U.S. Federal Communications Commission
Note: This equipment has been tested and found to comply with the limits for a Class A
digital device pursuant to Part 15 of FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with this instruction manual, may cause
harmful interference to radio communications. Operation of this equipment in a residential
area is likely to cause harmful interference in which case the user will be required to
correct the interference at his own expense.
Note: Modifications or changes not expressly approved of by the manufacturer or the FCC,
can void your right to operate this equipment.
Canadian Department of Communications
This digital apparatus does not exceed the Class A limits for radio noise emissions from
digital apparatus as set out in the radio interference regulations of the Canadian
Department of Communications.
Le présent appariel numérique n' émet pas de bruits radioélectriques dépassant les limites
appicables aux appariels numériques de Classe A. Prescrites dans le réglement sur le
brouillage radioélectrique edicte par le minestére des Communications Du Canada.
SAFETY
WARNING: ELECTRICAL NOTICES
ELECTRIC SHOCK HAZARD
To prevent ELECTRIC shock, do not remove cover. No user-serviceable parts inside. This
unit contains HAZARDOUS VOLTAGES and should only be opened by a trained and
qualified technician. To avoid the possibility of ELECTRIC SHOCK disconnect electric
power to the product before connecting or disconnecting the LAN cables.
Thisisa “CLASS 1 LED PRODUCT”
LIGHTNING DANGER
DANGER: DO NOT WORK on equipment or CABLES during periods of LIGHTNING
A Y.
CAUTION: POWER CORD IS USED AS A DISCONNECTION DEVICE.
TO DE-ENERGISE EQUIPMENT disconnect the power cord.
INSTALLATION
ELECTRICAL—AUTO VOLTAGE ADJUSTMENT
Lis product will automatically adjust to any voltage between the ranges shown on the
abel.
ELECTRICAL—TYPE CLASS 1 EQUIPMENT
THISEQUIPMENT MUST BE EARTHED. Power plug must be connected to a properly
wired earth ground socket outlet. An improperly wired socket outlet could place hazardous
voltages on accessible metal parts.
ELECTRICAL—CORD NOTICE
Use power cord, maximum 4.5 meters long, rated 6 amp minimum, 250V, made of HAR
cordage molded IEC 320 connector on one end and on the other end a plug approved by
the country of end use.
CAUTION: Air vents must not be blocked and must have free access to the room ambient
air for cooling.
Operating temperature
This product is designed for a maximum ambient temperature of 40° C.
ALL COUNTRIES: Install product in accordance with local and National Electrical
odes.
ASENNUS . Ca
SAHKO —AUTOMAATTINEN JANNITTEENSAATO
Tämä tuote säätää automaattisesti mihin tahansa jännitteeseen ohjetarrassa annettujen
arvojen välillä.
SAHKO —TYYPPILUOKAN 1 LAITTEET
TAMA LAITE TAYTYY MAADOITTAA. Pistoke täytyy liittää kunnollisesti
maadoitettuun pistorasiaan. Virheellisesti johdotettu pistorasia voi altistaa metalliosat
vaarallisille jánnitteille.
SAHKÓ —JOHTOON LIITTYVA HUOMAUTUS
Käytä seuraavanlaista virtajohtoa: maksimipituus 4,5 metriä, minimiteho 6 ampeeria, 250
V, valmistettu HAR-johdostosta, muovattu IEC 320 -liitin toisessa päässä ja kaäyttômaassa
hyváksytty pistoke toisessa pádssá.
HUOMAUTUS: IImavaihtoreikiá ei pidá tukkia ja milla táytyy olla vapaa yhteys
ympärôdivään huoneilmaan, jotta ilmanvaihto tapahtuisi.
KAYTTOLAMPOTILA
Tämä tuote on suunniteltu ympärôivän ilman maksimilämpôtilalle 40“ C.
KAIKKI MAAT: Asenna tuote paikallisten ja kansallisten sähkôturvallisuusmääräysten
mukaisesti.
> >
ENERGIA IRRADIATA
Questo prodotto commerciale & stato collaudato e risponde ai requisiti U.S.A. per
dispositivi di classe A.
NORME DI SICUREZZA
AVVERTENZE ELETTRICHE
PERICOLO DI SCOSSE ELETTRICHE
Per evitare SCOSSE ELETTRICHE non asportare il coperchio. Le component: interne
non sono riparabili dall'utente. Questa unita ha TENSIONI PERICOLOSE e va aperta
solamente da un tecnico specializzato e qualificato. Per evitare ogni possibilita di SCOSSE
ELETTRICHE, interrompere l'alimentazione del dispositivo prima di collegare o staccare
1 cavi LAN.
Questo ё un “Prodotto con LED di Classe I”
PERICOLO DI FULM INI
PERICOLO: NON LAVORARE sul dispositivo o sui CAVI durante PRECIPITAZIONI
TEMPORALESCHE.
ATTENZIONE: IL CAVO DI ALIMENTAZIONE E USATO COME DISPOSITIVO DI
DISATTIVAZIONE. PER TOGLIERE LACORRENTE AL DISPOSITIVO staccare il
cavo di alimentazione.
INSTALLAZIQNE
ELETTRICITA—REGOLAZIONE AUTOMATICA DELLA TENSIONE
Questo prodotto regolerá automaticamente la tensione ad un valore compreso nella gamma
indicata sull’etichetta.
ELETTRICITA—DISPOSITIVI DI CLASSE 1
QUESTO DISPOSITIVO DEVE AVERE LA MESSA A TERRA. La spina deve essere
inserita in una presa di corrente specificamente dotata di messa a terra. Una presa non
cablata tn maniera corretta rischia di scaricare una tensione pericolosa su parti metalliche
accessibili.
ELETTRICITA—AVVERTENZA SUL CAVO
Usare un cavo della lunghezza massima di metri 4,5, con capacità minima di 6 À, 250 V, di
filo HAR, dotato di connettore stampato IEC 320 ad un’estremita e di spina approvata dal
paese di destinazione all’altra.
ATTENZIONE: Le prese d'aria non vanno ostruite e devono consentire il libero ricircolo
dell’aria ambiente per il raffreddamento.
TEMPERATURA DI FUNZIONAMENTO
Questo prodotto è concepito per una temperatura ambientale massima di 40 gradi
centigradi.
TUTTI I PAESI: installare il prodotto in conformita alle vigenti normative elettriche
nazionali.
Allred
Telesyn
CentreCOM
Fiber Optic
Micro Repeaters
AT-MR116F
AT-MR117F
AT-MR118FT
AT-MR126F
AT-MR127F
AT-MR128FT
User Manual
© Copyright 1995 Allied Telesyn International Corp.
All rights reserved. No part of this publication may be reproduced without prior written
permission from Allied Telesyn International Corp.
Allied Telesyn International Corp. (ATI) reserves the right to make changes in
specifications and other information contained in this document without prior written
notice. The information provided herein is subject to change without notice. In no event
shall ATI be liable for any incidental, special, indirect, or consequential damages
whatsoever, including but not limited to lost profits, arising out of or related to this manual
or the information contained herein, even if ATI has been advised of, known, or should have
known, the possibility of such damages.
Trademarks: CentreCOM is a registered trademark of Allied Telesyn International Corp.
Ethernet is a registered trademark of Xerox Corporation. UNIX is a registered trademark
of UNIX System Laboratories. Novell and NetWare are registered trademarks of Novell,
Inc. Microsoft and MS-DOS are registered trademarks and LAN Manager and Windows for
Workgroups are trademarks of Microsoft Corporation. 3Com is a registered trademark of
3Com. PC-NFS is a trademark of Sun Microsystems, Inc. PC/TCP is a registered trademark
of FTP Software, Inc. DECnet is a registered trademark of Digital Equipment Corporation.
Table of Contents
Electrical Safety and Installation Requirements ....................................... 1
Chapter 1
Overview oii e e eee eee reee eee eee e eee eee 1
The CentreCOM Micro Repeater Family oo... cece, 2
External Power Supply ............. enaoocoooononenaorcaooeocanea ceo eeeceanaacerarecocerecenecesorerecreneo 3
Internal POWer SUPPLY oes eee 3
The AT-MR116F and AT-MR126F ……....…ireresrerrerreneerensrrenrrrrnaesranne san e resserre 3
Activity LEDS .….………rrcrercrrcermmmencenseniererereranressressennneensenaereenrrsanrcacensenasrens rence D
The AT-MR117F and AT-MRI12TFE .................. een nene eee eee era er re eee eee 7
The AT-MR118FT and AT-MR128FT …..…....…rrsrereraserrennerensereenarrrrssansrrasrraaararanccranes 9
Chapter 2
Connectivity o.oo eee eee EA periienaceooecacanacenone nenes 13
Cable Types ...................e.remiemii e DI ee eee ee eee eere roer re errar 13
Fiber Optic 1I0OBASE-FL/FOIRL Cable -..............2.e.0em00 De 14
Configuration ......................eeiece ER EEE eee. 14
RJ45 Pin-Out Switch ............e..e..eeveei eee eee eee eee 15
Fiber Cable Connectivity .................e...eme e ee neo ee reee reee reee 16
OST OF SIMA eee Dee eee ener eee eee ree reree erre earn 16
Full- and Half-Repeater Mode of Operation ......................... ena e 17
The Four Repeater Rule .................eeeecn eee ener EEE 17
Full-Repeater Mode of Operation ………………eennnnnnnnnnnnnnnnnnn 17
Half-Repeater Mode of Operation ...................... e reee alero 17
Chapter 3
Troubleshooting ………..…..…..…....…….cicirracrmnansnnsnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnenee 19
Appendix À
Data Cabling Techniques een EEE 23
LOBASE-T N 23
UTP Port Wiring ….….rseressresnenennennnnmenennnnnnnnnnnnnnnnnnnnnnnnnnnen+n+e 24
10BASE-FL/FOIRL Ethernet ............. e... near ene re e ae reee. 28
I0BASES (Thick) Ethernet -.............. mine eee en nera eee a der aieiieir eee 28
AUT Drop Cables .....................ee eee e eee reee een e aerea 29
10BASE?2 (Thin) Ethernet ......................——— ene een eee rene ere a reader 29
XI
Appendix B
(CCT: 1 AS 31
Appendix C
Technical Support Fax Order .………..........…..…...…ncncnnenennnnnnnnnnnnnnn 37
Appendix D
CentreCOM Fiber Optic Micro Repeaters Manual Feedback ............. 39
15070 (> eee estes serrate essere ees erenerenenenenree recerca renace. 41
Where To Find US ….…................….…rrecrerronanseneerrererernensercerrrsenenmenseceesanre ses ncena neue 43
List of Figures
Figure 1: AT-MR116F Front Panel .…........….......rerserereeresersrecrorenensersccaracnensansessces 3
Figure 2: AT-MR116F Back Panel ..................eececcecreiere DD REITER RIE E E ee 4
Figure 3: AT-MR126F Front Panel .................e.e.00cercereree re ere eee nee 4
Figure 4: AT-MR126F Back Panel -..................eeeereiene eee eee nene eran eee, 5
Figure 5: AT-MR117F Front Panel ........ ieee eevee 7
Figure 6: AT-MRI117F Back Panel ..................eccccrcrcccr ce e er e e ee 7
Figure 7: AT-MR127F Front Panel ..............eescscccrercic ener e ee ee ee 8
Figure 8 AT-MRIZTF Back Panel ...... e e e ee e e 8
Figure 9: AT-MRI118FT Front Panel... e ee e eee. 10
Figure 10: AT-MR118FT Back Panel ...............e....nereccierrece ere e e ee 10
Figure 11: AT-MRI128FT Front Panel -................e....erececccic e eee ee eee. 11
Figure 12: AT-MR128FT Back Panel ........oo ieee 11
Figure 13: AT-MR126F to AT-MR117F Configuration ....................e000mecee me 14
Figure 14: AT-MR118FT to AT-MR128FT Configuration ................................. 15
Figure 15: Half-Repeater Mode of Operation ......................erec000re e DDD 18
Figure 16: 10BASE-T UTP Cabling Hub-to-MAU or NIC
(Straight-Through) ...................eee=ereeeeeie eee nee eceee eee rene 25
Figure 17: 10BASE-T UTP Cabling Hub-to-Hub (Crossover) ........................ 26
Figure 18: Hub-to-MAU Wiring Usable (A) and Unusable (B) ......................... 27
Figure 19: Pin 1 Orientation on an RJ45 Connector ...:..................eemecerii DD 28
List of Tables
Table 1: CentreCOM Fiber Optic Micro Repeaters ....................e.eie EEE 2
Table 2: AT-MR1x6F Fiber Optic Micro Repeaters ......................eier e. 6
Table 3: CentreCOM Micro Repeater Dimensions .....................0eeere DD 6
Table 4: CentreCOM Micro Repeater Weight ......................... ee 6
Table 5: AT-MR127F Fiber Optic Micro Repeaters .....................e.ei 9
Table 6: AT-MR1x8FT Fiber Optic Micro Repeaters ....................... e 11
Table 7: CentreCOM Cable Types ..................eeeeciin eee DA 13
Table 8: Usable and Unusable Twisted Pair Cable recu 24
Table 9: MDI and MDI-X Switch Settings for Common Connection .................. 27
Xi
Chapter 1
Overview
Welcome to Allied Telesyn! Your decision to purchase a member of Allied
Telesyn's family of CentreCOM Fiber Optic Micro Repeaters means that,
beginning now, you can not only optimize the operational limits of your existing
network but have just incorporated the ability to anticipate future growth. In
short, each two-port Micro Repeater has been designed with the present, as well
as the future, in mind.
Your Micro Repeater is more than just a cost-effective means of interconnecting
network devices to fiber optic cable. For example, you will find that each repeater
also includes these important features: collision management, an ability to repeat
and retime signals, to monitor individual link status and to automatically isolate
individual ports that experience problems. And finally, each repeater can
automatically resume operations when problems are corrected.
While the characteristics of each Micro Repeater will be discussed individually,
they all share these common features:
OU IEEE 802.3 compliant and Ethernet compatible
Industry -standard duplex fiber optic cable
Choice of either an external or an internal power supply
Full- or half-repeater mode of operation
Either SMA or ST fiber optic (10BASE-FL/FOIRL) connectors
Automatic segment partitioning and jabber lock-up protection
Desktop, wall or 19 inch rack mountable using optional rackmount kits
LC CCC
Instantaneous visual check of power, port status, collisions and network
activity through front-mounted LEDs
UU State-of-the-art technologies, including custom Application Specific
Integrated Circuits (ASIC) and Surface Mount Technology (SMT)
The ability to repeat and retime data packets, regenerate the preamble
and extend collision fragment enforcement
J One year warranty
The CentreCOM Micro Repeater Family
The CentreCOM Fiber Optic Micro Repeater family consists of six repeaters:
D The AT-MR116F and the AT-MR126F support IEEE 10BASE-FL/Fiber
Optic Inter-Repeater Link (FOIRL) to AUI (10BASES) connectivity.
OU The AT-MR117F and the AT-MR127F support IEEE 10BASE-FL/
FOIRL to 10BASEZ (thin Ethernet) segments.
J The AT-MR118FT and the AT-MR128FT support IEEE 10BASE-FL/
FOIRL to 10BASE-T Unshielded Twisted Pair (UTP) connections.
Micro Repeaters is the power supply: the AT-MR11xF has an external
ме The difference between AT-MR11xF and AT-MR12xF CentreCOM
power supply, the AT-MR12xF has an internal power supply — a
feature that is consistent with each model in the entire Micro Repeater
family. Because of the external power supply, the AT-MR11xF can be
slightly smaller and weigh less if this should be a requirement.
Table 1 summarizes the differences among the models.
Table 1: CentreCOM Fiber Optic Micro Repeaters
Power
Model Supply Port 1 Port 2
AT-MR1x6F External or 10BASES 10BASE-FL/FOIRL
Internal ( AUI) (SMA or ST)
AT-MR1x7F External or 10BASE2 10BASE-FL/FOIRL
Internal (BNC) (SMA or ST)
AT-MR1x8FT External or 10BASE-T 10BASE-FL/FOIRL
Internal (UTP) (SMA or ST)
The choice between either an internal or external power supply is a function of the
physical characteristics of your particular networking environment such as
whether you want the unit to be rack, wall or surface mounted. Regardless of which
unit you have purchased, both will mount in a standard 19-inch rack (with cables
facing either front or back) or on any horizontal surface such as a shelf or table. In
short, since both hubs are only 1.2 inches high (less than one rack space), they
require very little space regardless of the mounting configuration.
External Power Supply
AT-MR116F, AT-MR117F and AT-MR118FT Micro Repeaters have an external
universal AC input/DC output power supply. This means they can be used with any
100-240 VAC, 50/60 Hz outlet (a power cord is provided with all models that are
intended for use in the United States).
manufacturer’s power adapter your Micro Repeater may be
damaged. This would also void your warranty and Safety Compliance
Certifications.
Not Y Use the AC power adapter that is provided. If you use another
ote:
Internal Power Supply
AT-MR126F, AT-MR127F and AT-MR128FT Micro Repeaters have an internal
universal AC input/DC output power supply which can be used with any 100-240
VAC, 50/60 Hz outlet (a power cord is provided with all models that are intended
for use in the United States).
The AT-MR116F and AT-MR126F
AT-MR116F and AT-MR126F CentreCOM Micro Repeaters are two-port
Ethernet media converters of network transmissions based upon thick Ethernet
Attachment Unit Interface (AUT) cable which typically connects a transceiver
attached to a coaxial segment to a workstation and fiber optic (10BASE-FL/
FOIRL) cable. The characteristics of both types of cable are discussed in .
The front panel of the AT-MR116F CentreCOM Micro Repeater is shown in
Figure 1.
M9 COLLISION RECEIVE —) COLLISION RECEIVE D
Allied Tel |
Internationa TRANSMIT ON LINE |
а O | O O
CentreCOM™ PORT 1: AUI 10BASE-FL/FOIRL
MR 1 16F IEEE 802.3 MICRO REPEATER
Figure 1: AT-MR116F Front Panel
Figure 1 shows the power LED and activity LEDs (On Line, Collision, Receive,
Transmit) for both Port 1, the thick Ethernet AUI port and Port 2, the
10BASE-FL/FOIRL port (which also includes a Link LED). The diagnostic
indicators are common to all members of the CentreCOM Micro Repeater family
and are discussed more thoroughly later.
The back panel of the AT-MR116F CentreCOM Micro Repeater is shown in
Figure 2.
PORT 1 ave
Allied To
00000600586 nternationa
O | O CentreCOM OO
MICRO REPEATER
POWER
AUI -
PORT 2
|] 1 J ||
TX RX
REPEATER
10BASE-FUFOIRL
Figure 2: AT-MR116F Back Panel
The back panel of the Micro Repeater shows the power receptacle, Port 1 and
Port 2.
Port 1 is a thick Ethernet port and shows the AUI connector. Port 2 is the fiber
optic port and can be specified as either an ST or SMA interface connector: one for
receive (RX) and the other for transmit (TX). Port 2 also includes a user-selectable,
full- or half-repeater mode of operation switch. These features will be discussed in
more detail in .
The front panel of the AT-MR126F CentreCOM Micro Repeater is shown in
Figure 3.
MA (lie J ele
CentreCOM”
MR 126F
IEEE 802.3 MICRO REPEATER
PORT 1: AUI PORT 1: 10BASE-FL/FOIRL
Figure 3: AT-MR126F Front Panel
Figure 3 shows the power LED and activity LEDs (On Line, Collision, Receive,
Transmit and Link [on Port 2 only]) for both the AUT port and the 10BASE-FL/
FOIRL port.
The back panel of the AT-MR126F CentreCOM Micro Repeater is shown in
Figure 4.
= Ex ame tasse [Tr |
5 $] Cenrecom o
O-2-0 С MR126F |
TOBASE-FUFOIRL AUI EEE 802.3 MICRO REPEATER
Figure 4: AT-MR126F Back Panel
The back panel of the AT-MR126F Micro Repeater shows the power receptacle,
Port 1 and Port 2.
Port 1 is the thick Ethernet port and shows the AUI connector. Port 2 is the fiber
optic port and be specified as either an ST or SMA interface connector: one for
receive (RX) and the other for transmit (TX). Port 2 also includes a user-selectable,
full- or half-repeater mode of operation switch. These features are discussed in
more detail in .
Once your CentreCOM Micro Repeater and optional transceiver are installed, your
network will support the maximum data transmission distance as well as the
maximum number of allowable nodes — all in accordance with IEEE transmission
specifications. These parameters are discussed further in.
Activity LEDs
Link—This indicator will illuminate when a valid link is detected on the Receive
(RX) port of the fiber optic segment. The Link indicator must be illuminated on the
fiber optic devices at both ends of the segment for Ethernet data to flow.
Power—AC power provided to the Micro Repeater.
On Line—This indicator is illuminated when the port is ready for operation and is
not partitioned.
Collision—Indicates a collision detected at that port.
Receive—This indicator will flash whenever a packet is received on that port.
Brief flashes indicate low traffic levels.
Transmit—Indicates Micro Repeater transmitting a packet out of that port.
Table 2 summarizes the functional differences between the four models of the
AT-MR116F and the AT-MR126F.
Table 2: AT-MR1x6F Fiber Optic Micro Repeaters
Model Power Port 1 Port 2
Supply
AT-MR116F-x1 External 10BASE5 10BASE-FL/FOIRL
(AU!) (SMA)
AT-MR116F-x3 External 10BASES 10BASE-FL/FOIRL
(AUI) (ST)
AT-MR126F-x1 Internal 10BASES 10BASE-FL/FOIRL
(AU) (SMA)
AT-MR126F-x3 Internal 10BASES 10BASE-FL/FOIRL
(AUI) (ST)
Aninternal power supply means that the AT-MR126F is slightly wider and heavier
than the AT-MR116F: it is 7.0 cm (2.8 in.) wider and 200 grams (7.0 0z.) heavier
than the AT-MR116F. The dimensions of the two repeaters are shown in Table 3.
Table 3: CentreCOM Micro Repeater Dimensions
Model Dimensions
AT-MR11xF 14.0 cm (5.5 in.) x 11.2 cm (4.4 in.) x 3.1 cm (1.2 in.)
AT-MR12xF 21.0 cm (8.3 in.) x 11.2 cm (4.4 in.) x 3.1 cm (1.2 in.)
The weights of the two repeaters are shown in Table 4.
Table 4: CentreCOM Micro Repeater Weight
Model Weight
AT-MR11xF 0.3 kg (10 07.)
AT-MR12xF 0.5 kg (1 Ib. 1 oz.)
The AT-MR117F and AT-MR127F
While both the AT-MR117F and AT-MR127F CentreCOM Micro Repeaters are
functionally similar to the AT-MR116F and AT-MR126F Micro Repeaters
respectively, they differ in the type of non-fiber optic media connectivity. The
AT-MR117F and the AT-MR127F employ 10BASE2 thin Ethernet cable as well as
fiber optic (10BASE-FL/FOIRL) cable. Thin Ethernet cable is discussed in.
Like both members of the AT-MR1x6F series, the AT-MR127F is functionally
identical to the AT-MR117F in all respects except for the power supply: the
AT-MR117F has an external power supply, the AT-MR127F has an internal power
supply. This means that the AT-MR127F is also slightly wider and heavier than the
AT-MR117F. As previously stated, the physical dimensions are the same for all
members of the Micro Repeater family and are shown in Table 3 and Table 4.
The front panel of the AT-MR117F CentreCOM Micro Repeater is shown in
Figure 5.
AY
Alied Te
Internationa
CentreCOM™ PORT 1: 10 BASE 2
MR 1 1 /F IEEE 802.3 MICRO REPEATER
10BASE-FL/FOIRL
Figure 5: AT-MR117F Front Panel
The front panel of the CentreCOM AT-MR117F Micro Repeater shows the power
and activity LEDs (On Line, Collision, Receive, Transmit and Link [on Port 2
only]) for both Port 1, the 10BASE2 (thin Ethernet port) and Port 2 (the
10BASE-FL/FOIRL port).
Figure 6 shows the back panel of the CentreCOM AT-MR117F Micro Repeater.
© 1
Al
ae (39) O
CentreCOM (39) O
MR117F
TERMINATOR IEEE 802.3
10 BASE 2 MICRO REPEATER POWER
Figure 6: AT-MR117F Back Panel
PORT 2
REPEATER AX
10BASE-FUFOIRL
The back panel of the AT-MR117F Micro Repeater shows the power receptacle,
Port 1, the BNC port — which includes a user-selectable 50 Q terminator switch
— and Port 2, the two fiber optic connections (again, with either two ST or two
SMA connectors).
means that an external BNC-T 50 Q terminator is not required when
Not The default of the 50 Q terminator switch on the BNC port is ON. This
ote 4
++ this switch is left in the default position.
The back panel also includes the user-selectable switch for either full- or half-
repeater mode of operation. The 50 Q terminator switch, as well as the full- or half-
repeater switch, will be discussed in more detail in .
The front panel of the AT-MR127F CentreCOM Micro Repeater is shown in
Figure 7. |
AVL ed ent с = —— == =D
er 9 O € o “To О oO D C=
IEEE 802.3 MICRO REPEATER PORT 1: 10 BASE 2 PORT 2: 10BASE -FUFOIRL
Figure 7: AT-MR127F Front Panel
Figure 7 shows the power LED and activity LEDs (On Line, Collision, Receive,
Transmit and Link [on Port 2 only]) for both Port 1, the thin Ethernet (BNC) port
and Port 2, the fiber optic port.
The back panel of the AT-MR127F CentreCOM Micro Repeater is shown in
Figure 8.
5 | ABE
IEEE 802.3 MICRO REPEATER
Figure 8: AT-MR127F Back Panel
The back panel of the AT-MR127F Miero Repeater shows the power receptacle,
Port 1, the BNC port — including the 50 Q termination switch — and Port 2, the
two fiber optic connections (again, either two ST or two SMA connectors). There is
also the user-selectable switch for either full- or half-repeater mode of operation.
These features will be discussed in more detail in .
Table 5 summarizes the functional differences between the AT-MR117F and the
AT-MR127F.
Table 5: AT-MR1x7F Fiber Optic Micro Repeaters
Power
Model Supply Port 1 Port 2
AT-MR117F-x1 External 10BASE? 10BASE-FL/FOIRL
(BNC) (SMA)
AT-MR117F-x3 External 10BASE? 10BASE-FL/FOIRL
(BNC) (ST)
AT-MR127F-x1 Internal 10BASE? 10BASE-FL/FOIRL
(BNC) (SMA)
AT-MR127F-x3 Internal 10BASE2 — 10BASE-FL/FOIRL
(BNC) (ST)
The AT-MR118FT and AT-MR128FT
Both AT-MR118FT and AT-MRI128FT Micro Repeaters are functionally identical
to the other members of the Micro Repeater family respectively with the exception
of the non-fiber optic media connectivity.
AT-MR118FT and AT-MRI128FT Micro Repeaters employ a 10BASE-T UTP wire
medium.
Like the AT-MR1x6F series as well as the AT-MR1x7F series, the AT-MR118FT
1s functionally identical to the AT-MR128F'T in all respects except for the power
supply: the AT-MR118FT has an external power supply, the AT-MR128FT has an
internal power supply. As previously stated, the physical dimensions are the same
for all members of the Micro Repeater family and were given in Table 3 and
Table 4.
The front panel of the AT-MR118FT CentreCOM Micro Repeater is shown in
Figure 9.
MAY? RECEIVE >)
(Allied ario a TRANSMIT
О J C=
CentreCOM™ PORT 1: 10BASE-T
MR 1 18FT IEEE 802.3 MICRO REPEATER
PORT 2: 10BASE-FL/FOIRL
Figure 9: AT-MR118FT Front Panel
The front panel of the AT-MR118FT CentreCOM Micro Repeater shows the power
LED and activity LEDs (On Line, Collision, Receive, Transmit and Link) for both
the 10BASE-T (Port 1) and the 10BASE-FL/FOIRL (Port 2) receptacles.
The back panel of the AT-MR118FT CentreCOM Micro Repeater is shown in
Figure 10.
PORT 2 PORT 1 AVS
ga
= — nternationa
RJ45 PIN-OUT CentreCOM O O
wae [Jeu 0 MDI X MRTISFT OO
MICRO REPEATER
TX REPEATER AX
10BASE-FL/FOIRL 10 BASE-T POWER
Figure 10: AT-MR118FT Back Panel
The back panel of the Micro Repeater shows the power receptacle. It also shows
Port 1, the 10BASE-T port, including the RJ45 pin-out, a straight-through/cross-
over cable selection switch (MDI/MDI-X) and Port 2, the two 10BASE-FL/FOIRL
connections (again either two ST or two SMA connectors). Port 2 also includes the
user-selectable switch for either full- or half-repeater mode of operation. All of
these features are discussed in more detail in .
10
The front panel of the AT-MR128F T 1s shown below in Figure 11.
AVES EE
CentreCOM”
MR128FT
IEEE 802.3 MICRO REPEATER
PORT 1: 10OBASE T PORT 2: 10BASE FL .FOIRL
Figure 11: AT-MR128FT Front Panel
The back panel of the AT-MR128FT is shown below in Figure 12.
MAYO 252)
CentreCOM” POWER
MR128F T
Figure 12: AT-MR128FT Back Panel
PORT 1
RAS PIN-OUT
wo [Jo ul
10BASE-T
Table 6 summarizes the differences between the AT-MR118FT and the
AT-MR128FT.
Table 6: AT-MR1x8FT Fiber Optic Micro Repeaters
Model Power Port 1 Port 2
Supply
AT-MR118FT-x1 External 10BASE-T 10BASE-FL/FOIRL
(RJ45) (SMA)
AT-MR118FT-x3 External 10BASE-T 10BASE-FL/FOIRL
(RJ45) (ST)
AT-MR128FT-x1 Internal 10BASE-T 10BASE-FL/FOIRL
(RJ45) (SMA)
AT-MR128FT-x3 Internal 10BASE-T 10BASE-FL/FOIRL
(RJ45) (ST)
11
Chapter 2
Connectivity
Cable Types
Four types of cable can be used with CentreCOM Fiber Optic Micro Repeaters:
A Fiber optic (10BASE-FL/FOIRL)
CCC
Thick Ethernet (10BASES)
Thin Ethernet (10BASE2)
UTP (10BASE-T)
While each type of cable has different advantages and characteristics, they all
adhere to IEEE 802.3 specifications. The primary consideration of each type of
cable is generally economic: the more expensive the cable, the greater the
advantages in terms of the number of available nodes, security, interference
protection and maximum distances.
Each type of cable is shown in Table 7.
Additional details of cabling techniques and port specifications for IEEE 802.3
media are contained in Appendix A on page 23, and should be referred to before
installing your network.
Table 7: CentreCOM Cable Types
Model Power Port 1 Port 2
Supply
AT-MR1x6F External or 10BASE5 10BASE-FL/FOIRL
Internal (AUI) (SMA or ST)
AT-MR1x7F External or 10BASE? 10BASE-FL/FOIRL
Internal (BNC) (SMA or ST)
AT-MR1x8FT External or 10BASE-T 10BASE-FL/FOIRL
Internal (RJ45) (SMA or ST)
13
Fiber Optic 10BASE-FL/FOIRL Cable
In general, fiber optic cable:
J Isimmune to electromagnetic interference
J Can span longer distances without attentuation
J Eliminates grounding problems
J Is secure from unauthorized taps
Configuration
The configuration in Figure 13 demonstrates how an AT-MR126F (or
AT-MR116F) and an AT-MR117F (or AT-MR127F) can be used to link two
networks.
Building Backbone
50 © TOBASES Lh so
Terminator XCVR | Terminator
a
or == a ABST) ||
O20 —— CRS | 0 J
2,000 Meters Max.
Multimode
Fiber Optic Cable
(020) HO EE)
LEGEND
10BASES —
10BASE-FL
AUI drop
Figure 13: AT-MR126F to AT-MR117F Configuration
14
The configuration in Figure 14 demonstrates how an AT-MR118FT and an
AT-MR128FT can be used to link two networks. Note that, when thick Ethernet
10BASES connections are joined with a different medium such as 10BASE-T,
10BASE-FL, ete., an appropriate transceiver must be employed. In this instance,
Allied Telesyns’ Fiber Optic CentreCOM Micro Transceiver (AT-MX25F or
AT-MX26F) would fulfill this requirement as would any equivalent transceiver
from any other source.
Building Backbone
so 10BASES О 50 ©
Terminator XCVR Terminator
AUVUTP hub
of A
Ad
am onan."
ua.
(am DD
LEGEND
10BASES sess
10BASE-T +-----------
10BASE-FL — 7 —
AUI drop
Figure 14: AT-MR118FT to AT-MR128FT Configuration
activated (MDI = ON) on both AT-MR118FT and AT-MR128FT Micro
Repeaters, thus enabling a hub-to-hub connection using straight-
through cable.
Note Uy This configuration assumes that the RJ45 Pin-Out switch has been
|
— 4
RJ45 Pin-Out Switch
The RJ45 Pin-Out switch on the back panels of the AT-MR118FT and
AT-MRI28FT Micro Repeaters converts Port 1 to an uplinkable port and,
therefore allows one hub to connect to another hub in a star topology without the
use of special cross-over cables. The default setting for the RJ45 Pin-Out switch is
MDI-X (standard RJ45 port).
15
If you want to use Port 1 to connect (uplink) two hubs, then the RJ45 Pin-Out
switch of only one hub must be set to the uplinkable position MDI. The MDI
position is basically a hub pin-out which automatically swaps the TX and RX pin-
outs such that they do not conflict with the TX and RX ports at the other end of a
straight-through cable.
If you connect a straight-through cable (or any cable for that matter) between two
hubs (or any two nodes), and the network LEDs do not indicate the passage of
packets, change the position of the MDI/MDI-X switch. The repeater will not be
harmed if the MDI switch is in the wrong position.
In the configuration shown in Figure 14 on page 15, two buildings are linked by
fiber optic cabling and the signals are distributed by UTP. This technique takes
advantage of the stronger fiber optic signal and the less expensive UTP signal
technique.
Fiber Cable Connectivity
CentreCOM Fiber Optic Micro Repeaters support 100/140 micron, 62.5/125 micron,
and 50/125 micron duplex optical fiber cable (‘duplex’ refers to fiber optic cable
pairs). Normally, duplex fiber optic cable is labeled TX or TD (transmit) and RX or
RD (receive). This means it has a dedicated transmit cable and a dedicated receive
cable. The receiving port (RX or RD) on one device must be mated to the
transmitting (TX or TD) port on a second device for proper connectivity.
Fiber Cable Length—The IEEE FOIRL (fiber-optic inter-repeater link)
standard limits a fiber segment length to 1 km. That is, the fiber optic cable that
connects two repeaters is limited to 1 km. On the other hand, the more recent
IEEE 10BASE-FL standard limits a fiber segment length to 2 km. Note, however,
that this only applies to topologies in which one 10BASE-FL node connects to
another 10BASE-FL node. If one end of a 10BASE-FL connection is to a FOIRL
connection the limitation would revert to the lesser distance of 1 km.
What will happen if you accidently connect the TX cable of one device to the TX
port of another device? Or RX to RX?
Nothing!
There will be no damage. The link port LED will not illuminate which means there
1S no connectivity.
ST or SMA
As previously noted, the fiber optic port can be ordered with either an ST or SMA
interface. The difference between the two is fundamental: an ST connector uses a
bayonet type interface; the SMA connector uses a screw-on, threaded interface.
On the other hand, while Allied Telesyn sells both ST and SMA connectors it
should be noted that many existing (usually older) networking environments use
SMA (or Biconic) connectors which are not physically compatible with ST
connectors.
16
The five common modular cable specifications and their applicability to 10BASE-T
network use are shown in Table $.
Table 8: Usable and Unusable Twisted Pair Cable
Cable Cable en Twist/ | 10BASE-T
Level | Description AC Character | Specification Fool OK?
1 Unshielded N/A CCITT None NO!
Untwisted
2 Individual 100 © +30 2 RS232 None NO!
UTP 1BASES AT&T
PDS
3 Typical 100 © +15 © T1, AT&T 3-5 YES
Individual ISDN
UTP 10BASE-T
IBM Type 3
4 Enhanced 100 Q +30 Q EIA, TIA 5-8 YES
Individual 10BASE-T
UTP NEMA
5 Individual 100Q+30Q EIA, TIA 8-10 YES
UTP 10BASE-T
UTP Port Wiring
The AT-MR118FT and AT-MR128FT both have a 10BASE-T UTP port with an
industry-standard RJ45 receptacle and a RJ45 pin-out switch. The RJ45 pin-out
straight-through (MDI)/crossover (MDI-X) switch enables you to use a straight-
through cable during hub-to-hub connectivity by simply placing the switch in the
MDI position.
24
RJ45 PIN RJAS PIN
Par IEEE 802.3 specifications
Figure 16: 10BASE-T UTP Cabling Hub-to-MAU or NIC (Straight-Through)
The standard connection when using a micro repeater is from a Data
Communications Equipment (DCE) device, such as the repeater, to a DTE device,
such as a workstation NIC. This configuration uses a straight-through cable (see
Figure 16) with the switch in the MDI-X position.
25
Some situations require a DCE-to-DCE connection, for example when hubs are
cascaded. This can be accomplished with a standard crossover cable, as illustrated
in Figure 17. By setting the switch to MDI, you may use a straight-through cable,
eliminating the need for making or obtaining a crossover cable.
RJ45 PIN
RJ45 PIN
Per IEEE 802.3 specifications
(1) TD +
[TE то -
3 RD +
(4) Not Used
(5) Not Used
(7) Not Used
Not Used
Note Y
Figure 17: 10BASE-T UTP Cabling Hub-to-Hub (Crossover)
The interface type that IEEE specifies as standard for a repeater such
as the AT-MR1x8F'Tis MDI-X. The straight-through/crossover switch
merely provides convenience to avoid having to obtain an alternate
cable in some applications. If you connect a cable and it does not work,
try changing the MDI switch. The rule of thumb is the total number of
crossovers must be odd. You cannot harm the repeater by having the
MDI switch in the wrong position.
Table 9 shows which position the straight-through/crossover selection switch
needs to be for the device configuration shown.
26
Table 9: MDI and MDI-X Switch Settings for Common Connection’
Model Connected to MDI MDI-X
AT-MR118FT/AT-MR128FT Hub X
AT-MR118FT/AT-MR128FT RJ45 Transceiver X
AT-MR118FT/AT-MR128FT NIC X
1. This table assumes a straight-through cable is being used. The switch setting are the opposite of
what is shown if a crossover cable is being used.
In both the crossover and straight-through instances, the wire is twisted pair.
Figure 18 demonstrates usable and unusable cable configurations for the straight-
through wire pairing in the UTP environment.
A
[1] Parr twisted as per Level 3, 4 or 5 cable.
RJ45 Pin RJ45 Pin
TDs (1) В (7 TD+
TD- O, a (2) TD-
This cable will not work for 10BASE-T.
Note that 3 and 6 are twisted, but are not a pair.
RJ45 Pin RJ45 Pin
то» O, — (1) то»
TD- (2) QE TD-
AD. (3) - —(3) RD-
No! Used (4) Q (4) Not Used
Not Used ( 5 (5) Not Used
© QA ro.
Not Used O - 7) Not Used
Not Used a (8) Not Used
Figure 18: Hub-to-MAU Wiring
Usable (A) and Unusable (B)
Diagram A is correct because the proper pairs are twisted together. Diagram B
1s Incorrect because the wires for the receive pair, pins 3 and 6, are not twisted
together. This could result in excessive common mode noise and an unacceptably
high data error rate.
27
If you pair pins incorrectly, for example as shown in Figure 18, Diagram B, your
network may have a high data error rate. In a straight-through cable, the transmit
pins, 1 and 2, are paired, as are the receive pins, 3 and 6. In a crossover cable (not
shown), pins 1 and 2, TD+ and TD-, are paired, as are pins 3 and 6, RD+ and RD-.
When pins 1 and 2 are crossed over, they connect to pins 3 and 6 respectively, and
pins 3 and 6, when crossed over, connect to pins 1 and 2 respectively.
See Figure 19 for the location of pin 1 so you can count your pins correctly.
On an RJ45 connector, it is important to know where pin 11s so you can count your
pins correctly. Figure 19 shows the location of pin 1.
Pin 1
Figure 19: Pin 1 Orientation on an RJ45 Connector
10BASE-FL/FOIRL Ethernet
The IEEE 802.3 10BASE-FL standard supports up to 2,000 meters (6,560 ft.) of
multimode duplex fiber optic cable in a point-to-point link which directly attaches
two devices. Duplex refers to support for fiber optic cable pairs, enabling a two-
cable fiber optic connection with transmit mode dedicated to one cable and receive
mode on the other. 10BASE-FL supports connections of 2,000 meters (6,560 ft.)
while Fiber Optic Inter-Repeater Link(FOIRL) supports connections of 1,000
meters (3,280 ft.). 10BASE-FL is compatible with FOIRL, but restricts distance to
1,000 meters (3,280 ft.) You can intermix 10BASE-FL and FOIRL nodes, but if the
cable connects a 10BASE-FL node at one end and a FOIRL node at the other, the
limitation would revert to the lesser distance of 1 km (3,280 ft.).
10BASES (Thick) Ethernet
When configuring 10BASES coax segments, IEEE 802.3 specifications allow 100
MAU attachments or less, spaced at multiples of 2.5 meters (8.2 ft.) measured
accurately from the cable end (50 Q terminator included). The 10BASES5 cable
segment cannot exceed 500 meters (1,640 ft.) in length. Worst case “end-to-end”
propagation delay of a 10BASES5 coax segment is 2165 ns. Propagation delay of
10BASES Ethernet coax is calculated at 4.33 ns/meter. Both ends of the segment
must be terminated with a 50 Q termination with a power rating of 0.5 watts or
greater. Earth grounding of the segment shield must take place at only one point
on the cable.
28
AUI Drop Cables
AUT or Drop cables can be no longer than 50 meters (164 ft.) each. Attachments
may be made only to the cable ends at the 15-pin D-shell connector. AUT cables
may have a maximum 257 ns propagation delay, as used for computing the worst
case propagation delay of a cable system. AUT cable propagation delay 1s
approximately 5.13 ns/meter. This cable internally consists of four shielded twisted
pair wires with an overall shield and drain wire; a 15-pin D-shell male connector at
one end and a 15-pin D-shell female connector at the other end. Cable impedance 1s
nominally 78 Q. The AUI cable typically connects a transceiver attached to a
coaxial segment to a DTE (workstation).
10BASE2 (Thin) Ethernet
When configuring thin coax segments, IEEE 802.3 specifications allow 29 or fewer
MA Us per cable segment spaced at no less than 0.5 meter (1.64 ft.). The 10BASEZ2
cable length cannot exceed 185 meters (607 ft.) per 10BASE2 cable segment. The
worst case propagation delay for a 185 meters (607 ft.) thin Ethernet segment is
950.9 ns. The propagation delay for 10B ASE2 Ethernet cable is 5.14 ns/meter. Both
ends of the segment must be terminated with a 50 Q termination with a power
rating of 0.5 watts or greater. Earth grounding of the segment shield must take
place at only one point on the cable.
29
Appendix B
Glossary
10BASE2—Also called thinnet Ethernet, thinnet or CheaperNet, a 10 MHz
baseband specification. Cable impedance is 50 Q and maximum coaxial segment
length is 185 meters (607 ft.).
10BASE5—AIso called thick Ethernet, a 10 MHz baseband specification. Cable
impedance is 50 Q and maximum coaxial segment is 500 meters (1,640 ft.). The cable
is commonly referred to as yellow cable. Thick Ethernet cable is typically used as
a trunk or backbone path of the network.
10BASE-FL—IEEE 802.3 Fiber Optic Ethernet. A fiber optic standard that
allows up to 2,000 meters (6,560 ft.) of multimode duplex fiber optic cable in a point-
to-point link.
10BASE-T—IEEE 802.3 UTP Ethernet. Using low cost Level 3 or better UTP
wiring, 100 meters (328 ft.) of point-to-point link segments are possible. Uses RJ45
connectors and sometimes 50-pin AMP connectors to a patch panel. Runs at 10
MHz.
50-PIN TELCO (RJ21)—This connector is very common in 10BASE-T wiring.
As opposed to the RJ45 connector, the 50-pin Telco connector concentrates up to
12 UTP connections onto one connection. This concentration of UTP ports is then
broken out for connection to a punch-down block inside a building’s wiring closet.
50-pin Telco connections provide a very clean, uncluttered interface to the
building’s wiring.
AT-ADAPT-2— A harmonica-style adapter that allows direct conversion from a
50-pin Telco connector to RJ45 receptacles. |
ATTACHMENT UNIT INTERFACE (AUI)—Connection between a MAU
(transceiver) and a DTE (typically a workstation). Includes a 15-pin D-sub
connector and sometimes a 15-conductor twisted pair cable. Maximum length is 50
meters (164 ft.).
BACKUP MODULE— A repeater that behaves as the management module
when the Master fails in a department concentrator.
BASEBAND COAXIAL SYSTEM—A system whereby information is directly
encoded and impressed on the coaxial transmission medium. At any point on the
medium, only one information signal at a time can be present without disruption.
BAYONET NUT COUPLE (BNC) CONNECTOR—A 10BASEZ2 thin coax
connector with push-on BNC locking lug that quickly locks into place with a half
twist.
2
DATA COMMUNICATION EQUIPMENT (DCE)—In RS232 specification a
module, such as a modem, for connecting a DTE to other equipment. A repeater
connected to a terminal or workstation for OMEGA LOCAL management use is
wired as a DCE.
DATA TERMINAL EQUIPMENT (DTE)—In RS232 specification a module
typically at the end of a segment. The DTE could be an Ethernet workstation,
repeater or bridge.
DEPARTMENT CONCENTRATOR—Hub which provides a large number of
workstation connections. The term, department concentrator, refers to multiple
repeaters housed in an AT-36C8 chassis. See Hub/Repeater, Repeater.
DIX CONNECTOR—See D-Sub Connector
FOIRL — A fiber optic standard that allows up to 1,000 meters (3,280 ft.) of
multimode duplex fiber optic cable in a point-to-point link.
HARMONICA ADAPTER—This adapter provides a simple way to convert the
50-pin Telco connection to RJ45 connections.
HEARTBEAT—See SQE
HOT SWAPPING— The process of replacing a hub module without bringing
down the network. This process occurs by sliding an active module into a fully
powered up concentrator, replacing a failed module.
HOUSE WIRING—House wiring is the existing wiring inside a building. This
wiring generally originates from one or more wiring closets such as a telephone
room. Some older buildings may have wiring unsuitable for 10 megabit data rates.
In these circumstances, it is recommended that the wiring is tested with a
10BASE-T signal/wire tester.
HUB/REPEATER—A hub is a central signal distributor. It is used in a wiring
topology consisting of several point-to-point segments originating from a central
point. The term hub is often used interchangeably with the term repeater.
Multiport 10BASE-T, 10BASEZ2 and fiber optic (10BASE-FL, FOIRL) repeaters
are considered hubs. See Repeater.
HUB-to-HUB WIRING—See MAU-to-MAU Wiring
HUB-to-MAU WIRING—UTP cables for 10BASE-T hub-to-MAU or NIC cards
are wired straight-through. An RJ45 receptacle at the hub would wire pin-to-pin
to the RJ45 receptacle at the MAU.
IMPEDANCE—An electrical characteristic of a circuit dealing with the
combination of the AC and DC resistance and the appearance of that resistance to
attached circuits.
JABBER LOCK-UP—The MAU's ability to automatically inhibit the transmit
data from reaching the medium if the transmit data time exceeds a specified
duration. This duration is in the range of 20 ms to 150 ms. Jabber lock-up protects
the medium from being overrun with data packets from a possibly defective device.
33
JAM—This is a term used to describe the collision reinforcement signal output by
the repeater to all ports. The jam signal consists of 96 bits of alternating 1s and Os.
The purpose is to extend a collision sufficiently so that all devices cease
transmitting.
JITTER—The fluctuation of the data packet in respect to a standard clock cycle.
Jitter is undesirable and must be minimized.
LINK SEGMENT—The link segment of coaxial cable is a segment which has no
MAU devices but links two LAN devices together such as repeaters.
LINK TEST—In 10BASE-T Ethernet there is a link test function that validates
the UTP link. This consists of a pulse transmitted from point A on one pair and
validated at point B. Point B also transmits a pulse on the second pair to be
validated by point A. These pulses occur during media idle states (in between
packets).
MANAGED MODULE— An intelligent repeater in a department concentrator
chassis that makes management data available to the Master.
MANAGEMENT AGENT—Software that is used to view hub activity and set
hub variables.
MASTER—A repeater in the top-most position in a department concentrator
chassis that contains and downloads the management agent software to Backup
and Slaves. The Master contains the only active image of the management agent
and controls the management functions of the Backup and Slaves.
MAU—See Medium Attachment Unit
MAU-to-MAU, HUB-to-HUB WIRING—10BASE-T MAU-to-MAU or hub-to-
hub wiring generally requires a crossover cable located somewhere along the UTP
cable run. This may commonly occur at the punch-down block or between the RJ45
wall receptacle and the workstation.
MAU/TRANSCEIVER— An Ethernet transceiver isa MAU. À 10BASE-T MAU
interfaces the UTP media to an AUI port on a workstation, repeater, bridge or
other Ethernet devices.
MDI/MDI-X—See Medium Dependent Interface
MEDIUM ATTACHMENT UNIT (MAU)—In a LAN, a device used in a data
station to couple the DTE to the transmission medium.
MEDIUM DEPENDENT INTERFACE (MDI)—The mechanical and electrical
interface between the trunk cable medium and the MAU. MDI-X is another
version of the interface that enables like devices to connect, using different pin-
outs, avoiding conflicts that occur when receiving and transmitting packets use the
same pin-out.
MODULE—A single repeater when it is mounted with other repeaters in an
AT-36Cx or AT-36 Ex department concentrator chassis.
34
N-SERIES—A barrel shaped, threaded connector used on 10BASES (thick
Ethernet) coaxial cable.
PATCH PANEL—A 10BASE-T patch panel may be between a punch-down block
and UTP workstation. The patch panel generally has a female RJ45 connector on
the front for each workstation anda Telco (RJ21) connector on the back, which are
wired to a punch-down block. This provides a convenient way for the installer or
network manager to connect the hub 10BASE-T ports into the desired building
locations.
PHYSICAL MEDIUM ATTACHMENT (PMA)—The portion of the MAU that
contains the functional circuitry.
PHYSICAL SIGNALING (PLS)—That portion of the physical layer contained
Within the DTE that provides the logical and functional coupling between MAU
and data link layers.
POLARITY CORRECTION—Many 10BASE-T UTP ports have a polarity
correction function. If the UTP wiring has RD-and RD+ inadvertently crossed, the
polarity correction function will sample the signal and electrically swap the wires.
If the TD- and TD+ wires are crossed, the correction would occur at the MAU on
the other end of the UTP link. This occurs within a single pair and should not be
confused with the crossover cable.
PROPAGATION DELAY—-The time it takes a signal to travel from the input of
a system component to the output. Usually measured in nanoseconds. IEEE 802.3
has specific propagation delay maximums for computing propagation budgets
when designing a LAN. Cable length plays a major role in propagation delay. [i.e,
a 50 meters (164 ft.) AUT cable has a maximum allowable propagation delay of 257
ns.] The propagation delay of cable is dependent on length and velocity factor of the
cable type. There are also propagation delays associated with electronics attached
to the system.
PUNCH-DOWN BLOCK—The punch-down block is the wiring panel where the
house wiring from the building’s offices terminates. This is where many 10BASE-T
hubs would be located. Wiring installers use a special punch-down tool to insert the
UTP wire for data and voice applications.
REPEATER—A device used to extend the length, topology, or Interconnectivity
of the physical medium beyond that imposed by a single segment, up to the
maximum allowable end-to-end trunk transmission line length. Repeaters perform
the basic actions of restoring signal amplitude, waveform and timing applied to
normal data and collision signals.
RJ45—This connector is a 10BASE-T standard for connecting UTP cabling. They
are Inexpensive and easy to install onto UTP cable.
SIGNAL QUALITY ERROR (SQE)—Also referred to as Collision or Collision
Presence. This occurs when two devices attempt to transmit at the same time
which is an illegal condition.
35
SIMPLE NETWORK MANAGEMENT PROTOCOL (SNMP)— SNMP is a
TCP/IP protocol that generally uses the User Datagram Protocol (UDP) to
exchange messages between a management information base and a management
client residing on a network. Since SNMP does not rely on the underlying
communication protocols, it can be made available over other protocols, such as
XNS or DECnet.
SLAVE— A repeater that behaves as a “dumb” module managed by a Master in a
department concentrator chassis. Slaves operating standalone perform only simple
regeneration and retiming tasks associated with repeating and are not
manageable.
SQE TEST—Commonly referred to as Heartbeat, is a special 802.3 signal sent by
the MAU to the DTE to test the collision detection function. Some DTE want SQE
and others do not. Repeaters do not want SQL Test.
STANDADLONE—Repeater operating as a hub on its own; i.e., not a module
among other modules in a department concentrator chassis.
STRAIGHT-THROUGH—A type of wiring connection where the pins of one
connector connect to the same pins of another connector. For example, pin 1 of
one connector connects to pin 1 of another connector.
TCP/IP PROTOCOLS—A set of protocols for inter-computer communication,
including network level (Internet Protocol), transport level (Transmission Control
Protocol or TCP), and application level protocols (for example, Telnet terminal
emulation). TCP/IP has been used for many years in two country-wide networks,
the ARPANET and MILNET. Recently, TCP/IP has become very popular with
users of a variety of multi-user computer systems and engineering workstations.
Most UNIX computers use TCP/IP over Ethernet as the main inter-computer
networking technology. TCP/IP is also popular among PC users, particularly as a
means of communication with large multi-user computers.
TELCO CONNECTOR— A 50-pin receptacle that plugs into the front of the hub,
enabling cables from external devices to connect to the hub.
THICK ETHERNET—See 10BASES
THIN ETHERNET—See 10BASE2
TRUNK CABLE—The trunk coaxial cable system.
UNMANAGED MODULE— A repeater that behaves as a “dumb” repeater in a
department concentrator chassis (i.e., without a Master). It performs simple
repeating tasks like packet retiming and regeneration, but is not managed.
UNSHIELDED TWISTED PAIR (UTP)—A cable used in 10BASE-T wiring
that consists of at least two twisted pairs of 22 to 26 AWG wire. The pairs should
have at least 3 twists per foot and have an impedance of 100 Q. Level 3 and Level
4 UTP cable generally fits these criteria.
36
Index
A
adapters
AT-ADAPT-2 45
harmonica 47
Telco 50-pin/RJ45 47
Application Specific Integrated Cir-
cuit (ASIC) 15
Attachment Unit Interface (AUI) 45
AUI 43, 46
AUI drop specification 43
B
baseband coaxial system 45
bit rate 46
bit time 46
C
cabling
10BASE2 43, 45
10BASES 45
10BASE-FL 27, 45
10BASE-T 45, 46
cross-over 46
FOIRL 27, 47
impedance 45, 47
straight-through 50
UTP (10BASE-T) 27
carrier sense 46
carrier sense multiple access with
collision detect (CSMA/CD) 46
coax segment 46
coaxial cable 46
coaxial cable segment 46
Collision 19, 30
collision presence 46
compatibility interface 46
compliance
four repeater rule 31
IEEE 802.3 45, 46
IEEE 802.3 specification 27
configuration
standalone 50
connectors
50-pin Telco 45, 47
bayonet nut couple connector 45
DIX 47
D-sub 46
N-series 49
RJ45 45, 47, 49
D
Data Communication Equipment
(DCE) 47
Data Terminal Equipment (DTE) 47
department concentrator 45, 47
DTE 43, 45, 46
E
Ethernet 42, 45
F
fiber optic 31, 45
H
harmonica adapter 47
hot swapping 47
hub/repeater 47
41
I
indicator
collision 46
heartbeat 47
link test 48
J
jabber lock-up 47
jam 48
jitter 48
L
LAN 46
link segment 48
M
managed module 48
management agent 48, 50
management agent 48
MAU 43, 46, 48
MAU/transceiver 48
MDI/MDI-X 48
Medium Attachment Unit (MAU) 48
Medium Dependent Interface (MDI)
48
module 48
backup 45
master 48
slave 50
O
On Line 19
P
Packet Retiming Controller (PRC) 31
patch panel 49
Physical Medium Attachment (PMA)
49
Physical Signaling (PLS) 49
polarity correction 49
Power 19
propagation delay 49
punch-down block 49
42
R
Receive 19
repeater 45, 48, 49, 50
full-repeater/half-repeater
31
repeater, full
full-repeater mode 31
switch
S
Signal Quality Error (SQE) 49
Simple Network Management Proto-
col (SNMP) 50
SQE test 50
Surface Mount Technology (SMT) 15
T
TCP/IP protocols 50
Telco connector 50
Transmit 19
U
unmanaged module 50
Unshieled Twisted Pair (UTP) 50
UTP 45
W
wiring 27, 43, 45, 46, 47, 50
AUI drop, specification 43
branch cable 46
house wiring 47
hub-to-hub 47
hub-to-MAU 47
MAU-to-MAU UTP, hub-to-hub 48
thick Ethernet 50
thin Ethernet 50
trunk cable 50
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