724-746-5500
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BLACK BOX
®
2 of 2
10/03/2010
#13071
»
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.
Features
The
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
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
OVERVIEW
Operating Features
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.
Item
Code
Stackable MiniHub
Le2801a
Stackable MiniHub-BNC
Le2801a-BNC
Stackable MiniHub-Fiber
Le2801a-FO
What’s included
✦
(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
T e c h S P e c S
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
