Cabletron Systems 100BASE-FX, Cabling Manual

Page: 63 / 192

10BASE5 (Coaxial Cable) 5-9
Ethernet Network Requirements
Grounding
Each thin coaxial cable segment should be connected to earth ground at only one
point. The connection to a ground should not be made through the BNC ports of a
network device or T-connector unless the connection to the ground is made
through the BNC terminator at the end of the cable. The grounding wire must be
connected to the outer metal shield of the coaxial cable and should be no longer
than 10 m (32.8 ft). If insulated, grounding wires should be green in adherence
with accepted wiring practice.
Length
10BASE2 specifications allow thin coaxial cable segments to be no longer than
185 m (606.7 ft). The use of longer cable segments can cause excessive error
conditions and poor network operation.
10BASE5 (Coaxial Cable)
The IEEE 802.3 10BASE5 specification details the use of thick coaxial cabling and
Attachment Unit Interface (AUI) cables. If a thick coaxial cable network does not
meet the requirements listed here, operation of the 10BASE5 networking
components may be adversely affected.
Cable Type
Cabletron Systems 10BASE5 transceivers are designed to be connected to IEEE
802.3-compliant 50
Ω
thick coaxial cable with a core gauge of 12 AWG. If
Cabletron Systems products are connected to other types of thin coaxial cable, the
10BASE5 network may be subject to errors and poor performance.
Termination
All 10BASE5 cables must be terminated at both ends of the cable with 50
Ω
terminators. Any time an N-Type barrel connector or intrusive tap is removed
from the thick coaxial cable segment, the segment or segments resulting from the
cable split must be either reconnected or terminated at the resulting ends. Failure
to terminate a thick coaxial cable segment can cause reflection of signal and the
creation of excessive error conditions.