Cabletron Systems THN-MIM - Manual (Page 12)

INSTALLATION
Page 2-3
• The THN-MIM7593 does not report false collisions to the IRM.
However, if a non-Cabletron Systems Ethernet device is connected
to the segment, it is possible for false collisions to be generated.
Non-Cabletron System devices should be thoroughly tested before
using them with the THN-MIM7593.
2.2.3 Thick-net Segments
• 50 ohm Ethernet type coaxial cable must be used when making up
thick-net cable segments.
• Each thick-net cable segment connected to a THN-MIM module
must be no longer than 500 meters (1640 feet) in length.
When making up networks requiring shorter cable runs, Ethernet
standard length 23.4, 70.2, and 117 meter cable sections should be
used. These cable sections may be connected together by a barrel
connector to form a cable segment.
Use of non-standard cable lengths may result in impedance
mismatches causing reflections to occur. These reflections may
cause data errors.
• A 50 ohm terminator must be connected to the far end of the thick
segment.
• A BNC to N-Series adaptor must be connected to the applicable
BNC port to attach the thick-net segment to the module.
• A maximum of 100 transceivers may be attached to a thick-net
cable segment, and these transceivers must be at least 2.5 meters
apart throughout the length of the cable. Transceivers should be
placed on the black bands that run along the cable that are marked
at 2.5 meter intervals.
• For safety, only one end of a thick-net segment should be connected
to earth ground. Connection to earth ground at more than one point
on the segment may allow for the occurrence of dangerous ground
currents. The BNC ports of the THN-MIM are connected to earth
ground. This eliminates the need for grounding a thick-net
segment connected to the module.