BNC cabling specifications
                                                                    v3.05


Specifications and recommendations for Thin Ethernet cable
==========================================================

Certain models of the EtherExpress(TM) PRO/10+ adapters have a
cylindrical, bayonet BNC connector.

BNC cabling is also known as thin Ethernet, RG-58A/U, Cheapernet, and
10BASE-2.

This document contains cabling and installation recommendations. For more
information on thin Ethernet cabling, contact your local network supplier
or call the IEEE at 1-800-678-IEEE.


Recommended cables
------------------

Here is a list of IEEE approved and non-approved cables:


Approved cable types
-----------------------------------------------------

802.3 10Base2  50 ohms, stranded tinned core

RG-58 a/u      50 ohms, stranded tinned core

RG-58 c/u      50 ohms, stranded tinned core

-----------------------------------------------------




Non-approved cable types
--------------------------------------------------

RG-58          50 ohms, solid center core

RG-58 u        50 ohms, solid center core

--------------------------------------------------




Installation recommendations
----------------------------

Thin Ethernet is a linear bus topology that uses a COAX cable.  A break
in the cable will disrupt the entire segment.  Each node is connected to
the cable using a T-connector.

-  Don't connect the end of the cable directly to the BNC connector on
the EtherExpress adapter.

-  Don't use cable drops or external transceivers unless you are using
the AUI connector instead of the BNC connector.

Both ends of a trunk must be terminated with 50 ohm terminators. One end
should be grounded.

Up to 5 trunk segments can be connected (through repeaters), but only 3
of these segments can have workstations attached.  Repeaters count as a
workstation so if you have two repeaters on a segment, the maximum number
of user workstations is 28.

Example:
                     no workstations               no workstations
                            |                             |
                            v                             v
      |--+--------+  +--------+  +------+-------+  +-------+  +----+----|
      |           |  |        |  |      |       |  |       |  |    |
      |         repeater     repeater   |     repeater   repeater  |
      |                                 |                          |
      workstation                   workstation              workstation
         1-29                          1-28                       1-29


Cable lengths
-------------

Max trunk length                   185 meters (607 feet)

Max number of nodes per trunk      30

Max number of trunks               5 (only 3 can have wkst. attached)

Max length of entire network       925 meters (3035 feet)
                                   (all trunks added together)

Min cable length between nodes     .5 meters (1 1/2 feet)