Cabletron Systems MicroMMAC 24T MICROMMAC- - Manual (Page 21)

REQUIREMENTS/SPECIFICATIONS
2-2
2.1.1 UTP Cable Specifications
The MicroMMAC-22T and MicroMMAC-24T lobe ports and the
TPIM-T2 support voice grade Unshielded Twisted Pair (UTP) cable, as
described in specifications for EIA/TIA TSB 568 and IBM Type 3 cable.
UTP consists of four pairs of 24 AWG solid wire for data or voice
communication and is typically used to wire cable runs within building
walls. In some installations, existing UTP building wiring can be used for
Token Ring cabling. UTP cable must conform to the limits shown in
Table 2-1.
WARNING : DO NOT connect UTP cabling to any non-Token Ring
network conductors (telephone, etc.) or ground. If in doubt, test wiring
before using. The voltages used in UTP telephone circuits present a shock
hazard and can damage Token Ring equipment when connected to Token
Ring cabling.
The increased popularity and cost advantages of UTP cable have driven
refinements in UTP cable design. Better grades of UTP cable, known as
supergrade or level 4, provide improved transmission characteristics and
may allow operation at 16 Mbps on longer lobe cables.
Attenuation and Impedance
The values listed in Figure 2-1 include the maximum attenuation of the
cables, connectors, patch panels, and reflection losses due to impedance
mismatches in the segment.
Table 2-1. UTP Voice Grade and Category 3 Specifications
Frequency Impedance Attenuation
1 MHz 100
Ω ±
15% <26 dB/km (8 dB/1000 ft)
4 MHz 100
Ω ±
15% <56 dB/km (16 dB/1000 ft)
10 MHz 100
Ω ±
15% <98 dB/km (30 dB/1000 ft)
16 MHz 100
Ω ±
15% <131 dB/km (40 dB/1000 ft)