Enterasys csx400 Benutzerhandbuch
Ethernet Cabling Requirements
50 CSX400 and CSX400-DC User’s Guide
10BASE-T Twisted Pair Network
When connecting a 10BASE-T segment to either of the CSX400 Ethernet interfaces (Twisted Pair
Ethernet Port Interface Module [EPIM-T]), ensure that the network meets the following
requirements:
Ethernet Port Interface Module [EPIM-T]), ensure that the network meets the following
requirements:
Length —
The IEEE 802.3 10BASE-T standard requires that 10BASE-T devices transmit over a
100 meter (328 foot) link using 22–24 AWG unshielded twisted pair wire. However, cable quality
largely determines maximum link length. If you use high quality, low attenuation cable, you can
achieve link lengths of up to 200 meters. Cable delay limits the maximum link length to 200
meters.
largely determines maximum link length. If you use high quality, low attenuation cable, you can
achieve link lengths of up to 200 meters. Cable delay limits the maximum link length to 200
meters.
Insertion Loss —
Between frequencies of 5.0 and 10.0 MHz, the maximum insertion loss must
not exceed 11.5 dB. This includes the attenuation of the cables, connectors, patch panels, and
reflection losses due to impedance mismatches in the link segment.
reflection losses due to impedance mismatches in the link segment.
Impedance —
Cabletron Systems 10BASE-T products work on twisted pair cable with
75-to-165 ohms impedance. Unshielded twisted pair cables typically have an impedance of
between 85 and 110 ohms. You can also use Shielded Twisted Pair cables, such as IBM Type 1
cable, but this cable has an impedance of 150 ohms.
between 85 and 110 ohms. You can also use Shielded Twisted Pair cables, such as IBM Type 1
cable, but this cable has an impedance of 150 ohms.
Jitter —
Intersymbol interference and reflections can cause jitter in the bit cell timing, resulting
in data errors. 10BASE-T links must not generate more than 5.0 ns of jitter. Make sure the cable
meets 10BASE-T link impedance requirements to rule out jitter as a concern.
meets 10BASE-T link impedance requirements to rule out jitter as a concern.
Delay —
The maximum propagation delay of a 10BASE-T link segment must not exceed
1000 ns. This 1000 ns maximum delay limits the maximum link segment length to no greater than
200 meters.
200 meters.
Crosstalk —
Signal coupling between different cable pairs within a multi-pair cable bundle
causes crosstalk. 10BASE-T transceiver design alleviates concerns about crosstalk, provided the
cable meets all other requirements.
cable meets all other requirements.
NOTE
Losses introduced by connections at punch-down blocks and other equipment reduce
total segment length. For each connector or patch panel in the link, subtract 12 meters
from the total length of the cable.
total segment length. For each connector or patch panel in the link, subtract 12 meters
from the total length of the cable.