Black Box LE2801A-FO, LE2801A-BNC, LE2801A User Manual

Stack five units to
support up to 40 users.

Includes eight
shielded RJ-45
connectors and one
AUI connector.
Optional BNC or
fiberoptic connectors
available.

Offers full 10BASE-T
functionality with an
exceptionally small
footprint.

LEDs show basic
network activity.

Durable steel
enclosure and
compact size.

T

he Stackable MiniHub is a

compact, unmanaged hub
offering low-cost connectivity for
IEEE 802.3/Ethernet 10BASE-T
networks. Each hub has eight
shielded modular jack ports and
one AUI port. A BNC or Fiber port
is optional in addition to the AUI.

Up to five hubs can be stacked
to form a single logical repeater
with 40 modular jack ports and
four AUI, BNC, or Fiber ports. This
feature allows you to build larger
networks without violating IEEE

802.3 guidelines.

Port 8, on the front of the
MiniHub, has an uplink switch for
internal crossing over of the
10BASE-T port. This allows you to

Stackable MiniHub

Ports

1

2

3

4

5

6

7

8

Stack Enable

LINK/TX

8

7

6

5

4

3

2

1

PORTS

PWR

COL

POL/TX

UP LINK

Off

IRB1

IRB2

On

PWR

12VDC, 1A

Build a 40-user network anywhere—or add up

to 40 users to your existing network.

Key Features

STACKABLE MINIHUB

connect to other hubs without
using a crossover cable.

It may be tiny, but the
Stackable MiniHub has
everything you expect in a
10BASE-T hub. Featuring full
repeater functionality, the
MiniHub also offers jabber
protection to prevent lockup from
excessively long packets,
automatic partitioning and
reconnection of ports
experiencing excessive collisions,
and automatic polarity detection
that compensates for wiring
errors on the receive pair.

To aid operation,
troubleshooting, and diagnostics,
the MiniHub has 20 front-panel
LEDs that display hub status and
link activity.

Typical Applications include:

• Networking a personal
multi-system office using
10BASE-T twisted-pair
cabling

• Temporary network for trade
shows

• Lab or office environments
that need an independent
Ethernet network

• Expanding small
independent networks

• Testing your network—use
the MiniHub as a test port

Black Box Corporation • 1000 Park Drive • Lawrence, PA 15055-1018 • Tech Support: 724-746-5500 • www.blackbox.com • e-mail: [e-mail]

© 2002. All rights reserved.

Black Box Corporation.

4/11/2002 #13071

• (1) Stackable MiniHub

• (1) External 120-VAC, 60-Hz
power supply

• (1) Velcro tape section,
approximately 3 inches
(7.6 cm) in length

• (2) Brackets for optional
wall-mounting

• (1) User’s manual

• (1) Stacking cable

Standards — All: 10BASE-T;

LE2801A: 10BASE5;
LE2801A-BNC: 10BASE2;
LE2801-FO: 10BASE-FL

Data Rate — 10 Mbps

Diagnostics — Via LEDs or network

software

Indicators — (18) Front-mounted

recessed LEDs:

(1) Power; (8) Link/TX

(1 for each port);

(8) Pol/RX (1 for each port)

Leads/Signals Supported — Pins 1,

2, 3, and 6

Partitioning — Automatic after 32

consecutive collisions

Reconnection — Occurs after 512

bits of error-free transmission

Maximum Segment Length —

UTP: 328 ft. (100 m);
STP: 492 ft. (150 m);
AUI drop cable: 164 ft. (50 m);
BNC: 607 ft. (185 m);
10BASE5: 1640 ft. (500 m);
10BASE-FL multi-mode

fiberoptic: 6562 ft. (2 km)

Connectors — All: (8) shielded

RJ-45, (1) DB15 female,
(2) stacking bus headers;

LE2801A-BNC: (1) BNC;
LE2801A-FO: (2) Fiber ST

User Controls — Rear-mounted

slide switch for straight­through versus crossover
(uplink) operation on port 8;

Stackable switch to specify

which hub is at the base of
the stack

Enclosure — High-strength steel

Cooling Method — Convection

MTBF — 50,000 hours

Temperature Tolerance —

Operating: 32 to 122°F (0 to 50°C);
Storage: -4 to +140°F (-20 to

+60°C);

Humidity: 10 to 95%,

noncondensing

Power — From wallmount power

supply: Input: 95–125 VAC, 60 Hz;
Output: 12 VDC, 1 amp;
Consumption: 10 watts maximum

Size — 1"H x 6.8"W x 4"D

(2.5 x 17.2 x 10.1 cm)

Weight — 1.3 lb. (0.6 kg);

With power supply: 2.3 lb. (1 kg)

The Complete Package

Operating Features

Specifications

Ordering Information

ITEM CODE

Stackable MiniHub ....................................................LE2801A

Stackable MiniHub-BNC ...............................LE2801A-BNC

Stackable MiniHub-Fiber ..................................LE2801A-FO

Stackable MiniHubs perform
signal amplification, retiming of
data packets, and regeneration of
preamble bits for each packet
received. They also detect
collisions, extend collision
fragments, and automatically
partition and reconnect individual
ports. This section describes a
few of these features in greater
detail.

Preamble Regeneration

As per Ethernet standards,
the MiniHubs add bits to the
preambles of output packets so
that each output packet contains
a minimum 64-bit preamble.

Collision Condition

When carrier is detected
simultaneously on multiple ports,
a jam pattern is generated on
each port to create a collision
condition. When a collision signal
from one port is detected, it
generates a jam pattern to other
ports.

Partitioning and Reconnection

Stackable MiniHubs will
automatically partition any port
where 32 consecutive collisions
occur or after 6.5 ms of
continuous transmissions.
Network integrity is checked
every 800 ms, and the segment is
reconnected after one 512-bit
packet is transmitted without an
error.

Fragment Extension

The Stackable MiniHubs will
automatically add bits to a
received data packet of less than
96 bits (a ”fragment”) so that the
size of the packet sent on toward
its destination is at least 96 bits.