Cabletron Systems NBR-420 - Manual (Page 67)

Network Cable Requirements
NBR-SERIES Installation Guide Page C-5
- Network propagation delay is the amount of time it takes a packet
to travel from the sending device to the receiving device. Total
propagation delay for the entire network must not exceed 25.6
µ
s
in one direction (51.2
µ
s round trip). If the total propagation delay
exceeds 25.6
µ
s, you must use bridges.
• Length - If you meet all system budgets, the maximum single mode
fiber optic cable length can reach 5 km (3.1 miles) with bridges at each
segment end. However, IEEE 802.3 FOIRL specifications specify a
maximum of 1 km (1093.6 yards).
C.1.4 Thin-Net Network
When connecting a thin-net (coaxial) segment to an EPIM-C, ensure your
network meets the following requirements:
• Cable Type - Use only 50 ohm RG58A/U type coaxial cable for
thin-net cable segments.
• Length - The thin-net segment must not exceed 185 meters.
• Terminators - Terminate each end of a thin-net segment.
• Connectors - You can use up to 29 tee-connectors throughout the
length of the cable segment for host connections.
- If you use an excessive number of barrel connectors within the
cable segment (e.g., finished wall plates with BNC feed-throughs),
you may need to reduce the number of host connections. For
special network design, contact Cabletron Systems Technical
Support.
- Grounding - For safety, ground only one end of a thin-net
segment. Do NOT connect EPIM BNC ports to earth ground.
Connecting a thin-net segment to earth ground at more than
one point could produce dangerous ground currents.