Chapter 2: Network Requirements
Impedance
Cabletron Systems 10BASE-T twisted pair products work on twisted pair cable with 75 to 165 ohms impedance. UTP cables typically have an impedance from 85 to 110 ohms. Shielded twisted pair cables, such as IBM Type 1 cable with an impedance of 150 ohms may also be used.
Temperature
Multi-pair PVC 24 AWG telephone cables typically have an attenuation of approximately 8–10 dB/100 m at 20°C (68°F). The attenuation of PVC insulated cable varies significantly with temperature. At temperatures greater than 40°C (104°F), use plenum-rated cable to ensure that attenuation remains within specification.
2.1.2100BASE-TX Twisted Pair Network
The 8H02-16 with an FE-100TX installed in ports 15 or 16 provides an RJ45 connection that supports UTP cabling. The device at the other end of the twisted pair segment must meet IEEE 802.3u 100BASE-TX specifications for the devices to operate at 100 Mbps. Use Category 5 UTP cabling for networks operating at 100 Mbps. Use Category 3, 4, or 5 UTP cabling for networks operating at 10 Mbps.
The 8H02-16 with an FE-100TX installed is capable of operating at either 10 or 100 Mbps. The FE-100TX senses the speed of the other device and adjusts its speed accordingly.
When connecting a 100BASE-TX twisted pair segment to port 15 or 16 with an FE-100TX interface module, the network must meet the following requirements:
Length
The IEEE 802.3u standard for 100BASE-TX requires that 100BASE-TX devices be capable of transmitting over a 100 meter (328 foot) link using Category 5 UTP cable.
The IEEE 802.3 standard for 10BASE-T requires that 10BASE-T devices be capable of transmitting over a 100 meter (328 foot) link using Category 3, 4, or 5 UTP cable.
