2-6
D
ESIGNING
AND
E
XPANDING
THE
N
ETWORK
Temperature
Use the following recommended cable types for the temperatures
specified:
■
UTP for 20 ° C
■
STP for 25 ° C
Also, adjust cable lengths downward for elevated temperatures.
Cabling Standards
The following sources recommend that all horizontal copper cable
runs (lobes) be limited in length to 100 meters:
■
Commercial building cabling standards, both domestic and
international (ANSI/EIA/TIA 568, TR-41 Working Groups, and
International Standard IEC/ISO 11801,
Generic Cabling for
Information Technology
)
■
Planning and Installation Guide Customer Premises Cabling to
Support Attachment of ISO 88025 Token Ring Stations
3Com supports these cabling practices and recommends customers
follow these guidelines.
Cable lengths listed in this chapter are valid only with cables as defined
by either the above-mentioned documents or by
EIA/TIA Bulletin:
Technical Systems Bulletin, Additional Cable Specifications for
Unshielded Twisted Pair Cables,
TSB-36, November 1991.
3Com Lobe
Cable Length
Recommendations
The horizontal lobe distance is the length of the furthest node from the
module. Use this information as follows:
1
Determine the longest lobe cable that can be included in your network.
2
Verify that all additional lobe cables are shorter than the maximum
length.
identifies maximum lobe lengths for 4 Mbps and 16 Mbps
networks using STP and UTP cables in a single closet configurations.
The lobe cable lengths in this table support the number of stations
listed in