Black Box LE14XXA User Manual

Black Box Modular Switches Installation and User Guide (8/99)

April 1999

LE14XXA

Modular Switches

Customer Call our Technical Support Specialists to discuss your application.

Support For 24-hour technical support: Call [phone] or Fax: [phone]

Information To order: Call [phone] 7:00 A.M. to 8:00 P.M. EST

Mail order: Black Box Corporation. 1000 Park Drive, Lawrence, PA 15055

i

Black Box Modular Switches Installation and User Guide (8/99)

Black Box

Modular Switches

Installation and User Guide

Trademarks

UL is a registered trademark of Underwriters Laboratories

Important: The LE14XXA Modular Switches contain no user-serviceable parts. Attempted
service by unauthorized personnel shall render any and all warranties null and void. If
problems are experienced with an LE14XXA, consult Section 6, Troubleshooting, of this User
Guide.

1999 Black Box Corporation

Printed in the United States of America.

______________________________________________________

Contacting Black Box Corporation

Please use the mailing address and phone and fax numbers listed below:

Black Box Corporation

1000 Park Drive

Lawrence, PA 15055

Phone: [phone]

Fax: [phone]

P/N 84-00020 (Rev A 08/99)

ii

Black Box Modular Switches Installation and User Guide (8/99)

from digital apparatus set out in the Radio Interference Regulation of the Canadian

FCC STATEMENT

FEDERAL COMMUNICATIONS COMMISSION

AND

CANADIAN DEPARTMENT OF COMMUNICATIONS

RADIO FREQUENCY INTERFERENCE STATEMENTS

This equipment generates, uses, and can radiate radio frequency energy and if not
installed and used properly, that is, in strict accordance with the manufacturer’s
instructions, may cause interference to radio communication. It has been tested and
found to comply with the limits for a Class A computing device in accordance with
the specifications in Subpart J of Part 15 of FCC rules, which are designed to provide
reasonable protection against such interference when the equipment is operated in a
commercial environment. Operation of this equipment in a residential area is likely to
cause interference, in which case the user at his own expense will be required to take
whatever measures may be necessary to correct the interference.

Changes or modifications not expressly approved by the party responsible for
compliance could void the user’s authority to operate the equipment.

This digital apparatus does not exceed the Class A limits for radio noise emission

Department of Communications.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les
limites applicables aux appareils numériques de classe A prescrites dans le
Règlement sur le brouillage radioélectrique publé par le ministère des
Communications du Canada.

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Black Box Modular Switches Installation and User Guide (8/99)

NORMAS OFICIALES MEXICANAS (NOM)

ELECTRICAL SAFETY STATEMENT

INSTRUCCIONES DE SEGURIDAD

1. Todas las instrucciones de seguridad y operación deberán ser leídas antes de que el

aparato eléctrico sea operado.

2. Las instrucciones de seguridad y operación deberan ser guardadas para referencia futura.

3. Todas las advertencias en el aparato eléctrico y en sus instrucciones de operación deben

ser respetadas.

4. Todas las instrucciones de operación y uso deben ser seguidas.

5. El aparato eléctrico no deberá ser usado cerca del agua—por ejemplo, cerca de la tina de

baño, lavabo, sótano mojado o cerca de una alberca, etc..

6. El aparato eléctrico debe ser usado únicamente con carritos o pedestales que sean

reconnendados por el fabricante.

7. El aparato eléctrico debe ser montado a la pared o al techo sólo como sea recommendado

por el fabricante.

8. Servicio—El usuario no debe intentar dar sercicio al equipo eléctrico más allá a lo descrito

en las instrucciones de operatión. Todo otro servicio deberá ser referido a personal de
servicio calificado.

9. El aparato eléctrico debe ser situado de tal mannera que su posición no interfiera su uso.

La colocación del aparato eléctrico sobre una cama, sofá, alfombra o superficie similar
puede bloquea la ventilación, no se debe colocar en libreros o gabinetes que impidan el
flujo de aire por los orificios de ventilación.

10. El equipo eléctrico deber ser situado fuera del alcance du fuentes de calor como radiadores,

registros de calor, estufas u otros aparatos (incluyendo amplificadores) que producen
calor.

11. El aparato eléctrico deberá ser connectado una fuente de poder sólo del tipo descrito en el

instrucivo de operación, o como se indique en el aparato.

12. Precaución debe ser tomada de mal manera que la tierra fisica y la polarización del equipo

no sea eliminada.

13. Los cables de la fuente de poder deben ser guiados de tal manera que no sean pisados ni

pellizcados por objetos colocados sobre o contra ellos, poniendo particular atención a los
contactos y receptáculos donde salen del aparato.

14. El equipo eléctrico debe ser limpiado únicamente de acuerdo a las recommendaciones del

fabricante.

15. En caso de existir, una antena externa deberá ser localizada lejos de las lineas de energia.

16. El cable de corriente deberá ser desconectado del cuando el equipo no sea usado por un

largo periodo de tiempo.

17. Cuidado debe ser tomado de tal manera que objectos liquidos no sean derramados sobre la

cubierta u orificios de ventilación.

18. Servicio por personal calificado deberá ser provisto cuando:

A: El cable de poder o el contacto ha sido dañado; u
B: Objectos han caído o líquido ha sido derramado dentro del aparato; o
C: El aparato ha sido expuesto a la lluvia; o
D: El aparato parece no operar normalmente o muestra un cambio en su

desempeño; o

E: El aparato ha sido tirado o su cubierta ha sido dañada.

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Black Box Modular Switches Installation and User Guide (8/99)

TABLE OF CONTENTS PAGE

1. SPECIFICATIONS.........................................................................................................1

1.1 Technical Specifications........................................................................................1

1.2 Model Information................................................................................................4

2. INTRODUCTION..........................................................................................................5

2.1 Inspecting the Package and Product......................................................................5

2.2 Product Description - Black Box Modular Switches...........................................6

2.2.1 Modular Switch chassis models ................................................................5

2.2.2 4-port modules, 100Mb fiber ...................................................................7

2.2.3 4-port module, 10 Mb fiber ......................................................................7

2.2.4 4-port module, RJ-45 (copper) ................................................................8

2.2.5 4-port modules, “3 + 1” , 3@RJ-45 and 1@fiber.....................................8

2.2.6 Frame Buffering and Latency ....................................................................9

2.3 Features and Benefits..........................................................................................11

2.4 Applications........................................................................................................12

3. INSTALLATION.........................................................................................................15

3.1 Locating the LE14XXA-Series Switches ............................................................15

3.2 Connecting Ethernet Media.................................................................................16

3.2.1 Connecting Fiber Optic ST-type “twist-lock”.........................................16

3.2.2 Connecting Fiber Optic SC-type “snap-in”..............................................17

3.2.3 Connecting Fiber Optic Single-Mode........................................................17

3.2.4 Connecting Twisted- Pair, RJ-45..............................................................17

3.3 Table-top or shelf mounting................................................................................18

3.3.1 Wall (or Vertical) Mounting..................................................................18

3.3.2 Rack-Mounting .....................................................................................18

3.4 Copper ports, Inernal jumper settings for 10/100Mbps ...................................19

3.5 Fiber ports, Internal Jumper settings for 100Mbps ..........................................20

3.6 Combo ports, Internal Jumper settings for RJ-45 & fiber 10 or 100Mbps .......21

3.7 Fiber ports, Internal Jumper settings for 10Mbps ............................................22

3.8 Powering the LE14XXA-Series Switches...........................................................23

3.9 4-port Module (4PM) Installation......................................................................24

3.9.1 Preparation for installing, changing and removing 4PMs......................24

3.9.2 Installing 4PM cards in the LE14XXA-Series chassis..........................26

3.9.3 Removing 4PM cards in the LE14XXA-Series chassis ........................27

4. OPERATION................................................................................................................29

4.1 Switching Funtionality........................................................................................29

4.2 Status LEDs........................................................................................................30

4.3 Manual switches for Up-link and Full/Half Duplex...........................................30

4.4 Auto-negotiation option for copper Fast Ethernet ports ..................................30

4.5 Auto-negotiation option for 10 Mbps ports HDX/FDX mode ........................32

4.6 Collision based flow control................................................................................32

4.7 Power budget Calculation for LE14XXA-Series 4PM’s Fiber media ................33

5. 4-PORT MODULES (AS SEPARATE ITEMS IN A SHIPMENT)................................34

5.1 Inspecting the Package and Product ...................................................................34

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Black Box Modular Switches Installation and User Guide (8/99)

5.2 Product Description ...........................................................................................34

5.2.1 LE1428C, 100Mb multi-mode FX-ST, “twist lock” connector...............35

5.2.1a LE1424C, 10 Mb multi-mode FL-ST, “twist-lock” connector...............35

5.2.2 LE1419C, 100Mb multi-mode FX-SC, “snap-in” connector..................36

5.2.3 LE1421C, 100Mb single-mode FX-SC, “snap-in” connector...................36

5.2.4 LE1422C, 100Mb FX Small-Form-Factor “plug-in” connector...............37

5.2.5 LE11423C, 100Mb FX Small-Form-Factor “plug-in” connector.............37

5.2.6 LE1425C, 10/100Mbps (RJ-45 for standard twisted-pair)......................38

5.2.7 LE1426C, “3TP+1F” Combo (Twisted Pair and 100Mb Fiber SC mm).39

5.2.8 LE1427C, “3TP+1F” Combo (Twisted Pair and 100Mb Fiber ST mm).39

5.2.9 LE1429C, “3TP+1F” Combo (Twisted Pair and 100Mb Fiber SC sglm)40

5.2.10 4PM -FP (Face Plate) ..............................................................................40

6.0 TROUBLESHOOTING.....................................................................................41

6.1 Before Calling for Assistance..............................................................................41

6.2 When Calling for Assistance...............................................................................41

6.3 Shipping and Packaging Information...................................................................42

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Installation and User Guide (08/99)

1. SPECIFICATIONS

1.1 Technical Specifications
Performance

Aggregate Filtering Rate: 2,380,800 frames/sec for 16 100Mbps ports
(for LE1416A)
(all ports are wire speed) 1,190,400 frames/sec for 8 100Mbps ports
(for LE1401A & LE1408A)
Aggregate Forwarding Rate: (for Modular Switch Fast Ethernet ports)
(all ports are wire speed) 1,190,400 frames per second, 16-port units
595,200 frames per second, 8-port units

Data Rate: 10 Mbps and 100Mbps
Address Table Capacity: 24K node addresses (12K on 8-port
models), with address aging
Packet buffer Size : 8 MB dynamic (4MB for 8-port)
Latency: 5 µs + packet time (100 to 100Mbps)
15 µs + packet time (10 to 10 Mbps, and 10 to 100Mbps)
Network Standards
Ethernet V1.0/V2.0 IEEE 802.3: 10BASE-T,
IEEE 802.3u: 100BASE-TX, 100BASE-FX

Maximum 10 Mbps Ethernet Segment Lengths
Unshielded twisted pair - 100 m (328 ft)
Shielded twisted pair - 150 m (492 ft)
10BASE-FL multi-mode fiber optic - 2 km (6,562 ft)
10BASE-FL single-mode fiber optic - 10 km (32,810 ft)

Maximum Standard Fast Ethernet Segment Lengths:
10BASE-T (CAT 3, 4, 5 UTP) - 100 m (328 ft)

100BASE-TX (CAT 5 UTP) - 100 m (328 ft)
Shielded twisted pair - 150 m (492 ft)

100BASE-FX, half-duplex, multi-mode - 412 m (1350 ft)
100BASE-FX, full-duplex, multi-mode - 2.0 km (6,562 ft)
100BASE-SX, short wavelength HDX m.m. - 300 m ( 935 ft)

100BASE-FX, half-duplex, single-mode - 412 m (1350 ft)

100BASE-FX, full-duplex, single-mode - 15.0 km (49,215 ft)

Connectors for copper wiring
Twisted Pair at 10/100Mb: RJ-45 shielded, female, front mounted
(for LE14XXA-Series Fast Ethernet copper ports, use Cat 5 cable)

Fiber Multi-mode connector types:

Fiber Port, SC-type (snap-in): Fiber optic multi-mode, 100BASE-FX

Fiber Port, ST-type (twist-lock): Fiber optic multi-mode, 100BASE-FX

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Installation and User Guide (8/99)

Fiber Port, MTRJ-type (plug-in):Fiber optic multi-mode, 100BASE-FX
Fiber Port, VF-45 type (plug-in): Fiber optic multi-mode, 100BASE-FX
Fiber Port, ST-type (twist-lock): Fiber optic multi-mode, 10ASE-FL

Fiber Single-mode connector types:

Fiber Port, SC-type: Fiber optic single-mode, 100BASE-FX

Manual switch-selections and jumpers
Up -link Push-button: Crossover sw for one RJ-45 port per LE1425C

Fiber default: Full-duplex (Internal jumpers may select HDX mode)
Copper default: Auto-negotiation (Internal jumpers may alternatively

-duplex, or fixed 100Mbps half-duplex)

LEDs: Per Port
LK: Steady ON when media link is operational

ACT: ON with receiver port activity
FDX/HDX: ON = Full-Duplex Mode
OFF = Half-Duplex Mode
100/10: ON = 100Mbps speed
OFF = 10 Mbps

Operating Environment

Ambient Temperature: 32° to 120° F (0° to 50°C)
Storage Temperature: -5°to 140°F (-20°to 60°C)
Ambient Relative Humidity: 10% to 95% (non-condensing)

Packaging

Enclosure:Rugged High strength metal. Suitable for stand-alone or rack-mounting

Dimensions: 1.75 in H x 17.0 in W x 9.0 in D (9.0 in W for QS580)

4.45cm H x 43.2cm W x 22.9cm D (22.5 cm W for QS580)
Weight: 4.0 lb. (1.8 Kg) for rack-mount models, 2.5 lb. for table-top
Cooling method: Fan cooled, @ 9 cfm

Power Supply (Internal)

AC Power Connector: IEC-type, male recessed, rear of chassis, with adjacent
manual ON-OFF switch (on AC model only)
Input Voltage: 110 to 240 VAC (auto-ranging)

Input Frequency: 47 to 63 Hz (auto-ranging)
Power Consumption: 20 watts typical (8 port model)
35 watts typical (16 port model)
Redundant power supplies available as options

48VDC Power Supply (Optional)

Power Input Voltage : 36 to 70 VDC (auto ranging)

Terminal Block in rear: “-, GND, +”

Power Consumption: same as for AC models, see above

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Black Box Modular Switches Installation and User Guide (8/99)

For Dual Source and Redundant DC supply options, see Appendices

For optional 23” Telco rack-mount brackets, order Model # RMB-23W
Agency Approvals

UL listed (UL1950), cUL, CE
Emissions meet FCC Part 15 Class A

Warranty Three years, return to factory Made in USA

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Installation and User Guide (8/99)

Model Information

Black Box Modular Switches

MODEL DESCRIPTION

LE1401A 8-port 10/100 Switch, holds up to two 4-port Modules with 4

LE1408A Same as Model LE1401A Switch, but in a 19” rack-mount package,

LE1416A Same as Model LE1408A, but with 24K-node address table and

LE14XXA-Series 4Port Modules
LE1419C Fiber module for LE14XXA-Series Switches, with four 100Mbps

LE1428C Fiber module for LE14XXA-Series Switches, with four 100Mbps

LE1421C Fiber module for LE14XXA-Series Switches, with four 100Mbps

LE1422C Fiber module for LE14XXA-Series Switches, with four 100Mbps

LE1423C Fiber module for LE14XXA-Series Switches, with four 100Mbps

LE1424C Fiber module for LE14XXA-Series Switches, with four 10 Mbps

LE1425C RJ-45 module for LE14XXA-Series Switches, with four 100Mbps

LE1426C 3TP+1F module for LE14XXA-Series Switches, with three

LE1427C 3TP+1F module, same as LE1426C but with fiber ST-type multi-

LE1429C 3TP+1F module, same as LE1426C but with fiber SC-type single-

switched ports each. Shelf or table-top mounting. For mixed-media
flexibility, combinations of RJ-45 and various fiber port connector
types, modes, and speeds can be configured. Full speed filtering
and forwarding at 100Mbps speed across all ports, self-learning
12K-node address table, and large 4MB packet buffers. Front­mounted LEDs, internal auto-ranging power supply

with mounting brackets.

8MB packet buffers. Holds up to four 4-port Modules (4PMs),
19” rack-mount package, with mounting brackets.

multi-mode FX SC connectors

multi-mode FX ST connectors

single-mode FX SC connectors

multi-mode FX “MTRJ” connectors

multi-mode FX “VF-45” connectors

multi-mode FL ST-type connectors

auto-negotiating RJ-45 ports, one of which has an up-link push­button

10/100MB auto-negotiating RJ-45 ports and one fiber port with
100Mbps multi-mode FX SC connector

mode connector

mode connector

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Black Box Modular Switches Installation and User Guide (8/99)

A

Remove the items from the shipping container. Be sure to keep the shipping container

contact Black Box. If the unit needs to

2. Introduction

2.1 Inspecting the Package and Product

Examine the shipping container for obvious damage prior to installing this product;
notify the carrier of any damage which you believe occurred during shipment or delivery.
Inspect the contents of this package for any signs of damage and ensure that the items listed
below are included.

This package should contain:

1 LE1401A, LE1408A, LE1416A Modular Switches
1 AC Power Cord (U.S. and other 115 VAC only)
1 Set of two wall-mounting brackets (for LE1401A Model only)
1 Set of metal “Ears” for optional “19” rack mounting (for LE1408A & LE1416

only)
1 Installation and User Guide (this manual),

should you need to re-ship the unit at a later date.
In the event there are items missing or damaged,

be returned, please use the original shipping container if possible. Refer to Section 6,
Troubleshooting, for specific return procedures.

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Installation and User Guide (8/99)

Product Description , 8-port and 16-port Modular Switches

Black Box LE14XXA series Modular Switches boost the performance of large Ethernet

-pair switched ports. Their “mixed-

lity provides for a variety of configurations including various types of fiber port

-45 (copper) ports in the same

-Port modules that can be integrated with a base

-media requirements for a 10/100 Switch product.
The Black Box LE14XXA-Series provide the switching speed and the reliability to

Box LE14XXA-Series

-Port Modules) for fiber types and for copper, as well as “3+1” combo (3 RJ-45 and

-Port Modules can be configured into a LE14XXA-Series Switch

-Series

Designed for use in departments with multiple workgroups, in remote offices and in

-Series Switches are easy to install and use. Addresses of

-mounted LEDs provide status information on each port.

-Series Switches provide high performance plug-and-play operation in convenient

-top and rack-mount packages.

LE14XXA-Series chassis models

The LE14XXA-Series Modular Switches come in three chassis sizes, an 8-port table-

-port rack-mount, and a 16-port rack-mount. Each is configurable with a selection of

-port (i.e., 4-port) modules, providing the capability of 4, 8, 12, and 16 switched ports. The

The 8-port LE1401A table-top chassis is compact in size and suitable for shelf-

-mountable

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Black Box Modular Switches Installation and User Guide (8/99)

mount units are typically used in larger network wiring

port LE1416A

-

Switches with two or four 4-port slots in the front, i.e., with a capacity of 8 or 16 switched
ports. The LE1408A and LE1416A rack­centers.

PWR ACT

Black Box LE1401A

FDX/HDX

Black Box LE1401A

Modular Switches

LK

1
2
3
4

8 Ports Table-Top

Fiber Switch

x

LK

1 2 3 41 2 3 4

ACT

100/10

FDX/HDX

Figure 2.2.1a: Front view, 8-port LE1401A
table-top, 8-port LE1408A and 16-

Modular Switches

Black Box LE1408A

Modular Switch

Fiber Switch

PWR

FDX/HDX

LK

1 2 3 4 1 2 3 4

1
2
3
4

LKACT

ACT

FDX/HDX

100/10

8-Port Rack Mount

ACT

FDX/HDX

Magnum QS5116

Magnum QS5116

Modular Switch

Fiber Switch

GARRETT
GARRETT

PWR

FDX/HDX

1
2
3
4

1 2 3 4

LK ACT

16-Port Rack Mount

FDX/HDX

1 2 3 4

ACT

LK

1
2
3
4

x

1 2 3 4 1 2 3 4ACT

LK

100/10 FDX/HDX

FDX/HDXBlack Box LE1416A

LK

1

2
3
4

ACT

Mixed-media combination modules (4-port modules with three fiber ports and one
twisted-pair port) are supported in all of the LE14XXA-Series Fiber Switch models. All 4Port
module manual-selection switches and LED’s are located on the front panel, with the IEC
standard AC power connector (and a manual ON - OFF power switch) located at the rear. Fan
driven cooling air flows left to right.

110-220

47-63Hz

1.0-0.5A

ON

VAC

OFF

110-220

47-63Hz

1.0-0.5A

ON

VAC

OFF

Figure 2.2.1b: Rear view - Black Box table-top & rack-mount 4-Series Switches

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Installation and User Guide (8/99)

-port modules, 100Mb fiber

FDX/HDX

1
2

3

4

1 2 3 4

ST-Type

ACTLK

ACT

FDX/HDX

1 2 3 4

1

LK

2
3
4

VF45-Small Form Factor

FDX/HDX

1
2
3

4

1 2 3 4

LK

ACT

1 2 3 4

LK

1
2

3
4

ACT

FDX/HDX

MTRJ-Small Form Factor

SC-Type

-Port Modules, LE1420C, LE1419C LE1423C LE1422C

In a fiber 4-port module, all of the fiber ports are of the same speed, the same multi- or

-mode, and the same connector type. Multi-mode 100Mbps models are available with ST,

-45 connectors. Single-mode 100Mbps models are available with SC

The 100Mb fiber 4-port modules on the Black Box LE14XXA-Series normally are set

-duplex mode for best fiber distance and performance. On the

-Series, the user may select full- or half-duplex mode per-port with an internal jumper

On Black Box fiber 4PMs, there are three LED’s per fiber port. The Link (LK) LED

eration” when lit, another LED indicates operation in full-duplex mode

-duplex), and an LED indicates Receiving Activity

-port modules, 10 Mb fiber

The 10 Mb model LE1424C fiber 4-port

8C, except

FDX/HDX

1

2
3

4

1 2 3 4

ACTLK

ST-Type

-FL standard, i.e., 2Km distance for multi-mode fiber.

-mode for 10km distance may be available as a special order).

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Black Box Modular Switches Installation and User Guide (8/99)

duplex mode at 10 Mb or at 100Mb speed if the device at the other

’s for each port. The LK (Link) indicates

“ready for operation” when lit, the ACT (Activity) indicates receiving activity on that port, the

45 10/100Mb port and a proper link (LK lit) must be made with the device at the other

on each

X) push

2.2.4 4-Port Module, RJ-45 (copper)

The Black Box LE14XXA-

1 2 3 4

LK

ACT

Series copper port module, model
LE1425C, provides four 10/100Mb

x

100/10 FDX/HDX

switched. RJ-45 ports. The 10/100Mb
switched ports are independently N-way auto-negotiating LE1425C

for operation at 10 or 100Mb speed in full- or half-duplex mode (as a default setting). They
independently move to half­end of the twisted pair cable is half-duplex or is not an auto-negotiating device.

On the model LE1425C , there are four LED

10/100 LED indicates operation at 100Mb speed when ON and at 10 Mb speed when OFF
(when auto-negotiation is not disabled), and the FDX/HDX LED is ON to indicate full-duplex
operation and OFF, to indicate half-duplex mode. A twisted pair cable must be connected into
each RJ­end of the cable in order for the LEDs to provide valid indications of operating conditions.

Internal jumper settings (See Section 3.4) allow technicians to over-ride the auto­negotiation feature and to manually set each port at full-duplex or half-duplex. One port
RJ-45 4-port module is equipped with a Media Dependent Interface-Crossover (MDI­button switch to simplify cascaded or up-link connections.

2.2.5 Combo 4 Port Modules, “3 + 1”, 3 RJ-45 and 1 fiber port

The combo 4-port modules are

LK

1 2 3 4

combination of copper and fiber media,
available as three 10/100 switched RJ-45

FDX/HDX

100/10

FDX/HDX

copper ports and one 100Mb switched
multi-mode fiber ST or SC port or single-mode SC port.
LE1426C

9

ACT

Installation and User Guide (8/99)

The RJ-45 ports run at 10/100Mbps with N-way auto-negotiation capability, whereas

- or full-duplex capability manually selected. The

-duplex. Internal jumpers settings allow technicians to set the 100Mb

-duplex mode. (See Section 3.4).

XA Combo 4-port modules, there are three LED’s for each RJ-45 port, which indicate

for the Fiber 4-

Frame Buffering and Latency

The Black Box LE14XXA-Series are store-and-forward switches. Each frame (or

ry and inspected before forwarding can occur. This

to be used for valid information.

While other switching technologies such as "cut-through" or "express" impose minimal

-through" technique permits collision fragment frames, which are a result of

indiscriminate cut-through forwarding is greater traffic congestion, especially at peak

-and-forward operation is that more bandwidth is available for good packets when the traffic

To minimize the possibility of dropping frames on congested ports, each Black-Box

-Series Switches dynamically allocates buffer space from an 8 MB memory pool,
y large buffer space for packet storage. (Many other

.) The other two LE14XXA-Series Switches LE1408A and LE1416A dynamically

-Series unit to be applied to all traffic

s, even when the traffic activity is unbalanced across the ports. Since the traffic on an

10