Utp reference, Utp wiring specifications, Table 7: usable and unusable twisted pair cable – Allied Telesis AT-TS24TR User Manual
Page 71: Appendix a
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Appendix A
UTP Reference
UTP Wiring Specifications
10BASE-T requires UTP wiring capable of supporting 10 Megabit data
rates. Use Level 3 or better UTP wiring throughout the 10BASE-T wiring
system. The wire should be 22 to 26 AWG, 100
Ω
impedance with 3 to 8
twists per foot. Typically, if a cable is flat, the pairs are untwisted and will
cause problems. A cable more or less round in section is likely to be
twisted.
The specifications of 6 common modular cables and their applicability to
10BASE-T network use are shown in Table 7. The maximum length for
10BASE-T UTP segments is 100 meters (328 ft.).
Table 7: Usable and Unusable Twisted Pair Cable
Cable
Level
Cable Description
AC Character
Specification
Twist/
Foot
10BASE-T
OK?
1
Unshielded untwisted
N/A
CCITT
N/A
NO!
2
Individual UTP
100
Ω
±
30
Ω
RS232 1BASE5
AT&T PDS
N/A
NO!
3
Typical Individual UTP
100
Ω
±
15
Ω
TI, AT&T ISDN
10BASE-T
IBM Type 3
3-5
YES
4
Enhanced Individual
UTP
100
Ω
±
30
Ω
EIA, TIA
10BASE-T
NEMA
5-8
YES
5
Individual STP
100
Ω
±
30
Ω
EIA, TIA
10BASE-T
8-10
YES
IBM
Type 1
Individual STP
150
Ω
PCC FT 1
N/A
NO!