MAKING NETWORK CONNECTIONS
Page 3-3
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Check the cable for continuity, and ensure that the cable is
actually a twisted pair cable.
•
Check that the adapter is properly seated in the expansion
slot.
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Check that the twisted pair connection meets dB loss and
cable specifications outlined in Section 3.1.2, below.
If a link still has not been established, contact Cabletron Systems
Technical Support (see Section 2.12, Getting Help).
3.1.2 Twisted Pair Requirements
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Length
- 10BASE-T transceivers must be able to transmit over
a 100 meter link (328 feet) using 24 AWG unshielded twisted
pair wire. 10BASE-T specifies no maximum link length.
NOTE:
Due to cable delay, the maximum link length is always
limited to about 200 meters (656 feet), regardless of the cable type.
Generally, links up to 150 meters (492 feet) long are achievable
for unshielded and shielded twisted pair cable. For each
connector or patch panel, subtract 12 meters (39.4 feet). This
allows links of up to 126 meters (413.4 feet) using standard 24
AWG UTP wire and two patch panels. Higher quality, low
attenuation cables may be required when using links greater
than 126 meters.
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Insertion Loss
- 11.5 dB maximum for a 10BASE-T link at all
frequencies between 5.0 and 10.0 MHz. This includes
attenuation of cables, connectors, patch panels, and reflection
losses due to impedance mismatches.
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Impedance
- Unshielded twisted pair cable is typically
between 85 to 110 ohms. Shielded cable, such as Type 1 cable,
is typically 150 ohms which can increase the signal reflection.
Cabletron Systems 10BASE-T Twisted Pair products will work
on shielded twisted pair cable with 75 to 165 ohms impedance.
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Jitter
- Not more than 5.0 nsec for a 10BASE-T link.
