Cabletron Systems EMM-E6 Ethernet manual 1 10BASE-T Twisted Pair Network

CHAPTER 2: REQUIREMENTS / CONFIGURATIONS

2.1.110BASE-T Twisted Pair Network

When connecting a 10BASE-T segment at any of the 10BASE-T hub ports or a 10BASE-T 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, it may be possible achieve link lengths of up to 200 meters. Cable delay limits maximum link length to 200 meters, regardless of the cable type.

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 your cable.

•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.

•Impedance - Cabletron Systems 10BASE-T Twisted Pair products work on twisted pair cable with 75Ω to 165Ω impedance.

Unshielded twisted pair cables typically have an impedance of between 85Ω and 110Ω. You can also use shielded twisted pair

cables, such as IBM Type 1 cable, but keep in mind that this cable has an impedance of 150Ω.

The high impedance of the IBM Type 1 cable increases signal reflection. However, due to cable shielding, and its subsequent lack of crosstalk between shielded pairs, this signal reflection has little effect on the quality of the received signal.

2-2 EMM-E6 User’s Guide