LevelOne MSL-3S79 - Manual (Page 63)

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Troubleshooting
This section is intended to help you solve the most common problems on MSL-3S79.
Incorrect connections
The switch port can automatically detect straight or crossover cable when you link
switch with other Ethernet device. As for RJ-45 connection, you should use correct
UTP or STP cable that 10/100/1000Mbps port uses 2-pairs twisted cable and Gigabit
1000T port uses 4 pairs twisted cable. If the RJ-45 connector is not correctly pinned on
right position then the link will fail. As for fiber connection, please notice the fiber cable
mode and fiber module should match.
Faulty or loose cables
Look for loose or obviously faulty connections. If they appear to be OK, make sure the
connections are snug. If that does not correct the problem, try a different cable.
Non-standard cables
Non-standard and miss-wired cables may cause numerous network collisions and
other network problem, and can seriously impair network performance. A category
5-cable tester is a recommended tool for every 100Base-T network installation.
RJ-45 ports: Use unshielded twisted-pair (UTP) or shield twisted-pair ( STP ) cable for
RJ-45 connections: 100 Ω Category 3, 4 or 5 cable for 10Mbps connections, 100 Ω
Category 5 cable for 100Mbps connections or Category-5e / Category-6 for above
1000Mbps connections. Also be sure that the length of any twisted-pair connection
does not exceed 100 meters (328 feet). Gigabit port should use Cat-5 or cat-5e cable
for 1000Mbps connections. The length does not exceed 100 meters.
Improper Network Topologies
It is important to make sure that you have a valid network topology. Common topology
faults include excessive cable length and too many repeaters (hubs) between end