Kingston Technology KNE24TX/RS, KNE12TX/RS, KNE8TX/RS manual Appendix D Commonly Asked Questions

Appendix D Commonly Asked Questions 21

Appendix D Commonly Asked Questions

Class I vs. Class II 100BASE-TX Fast Ethernet Repeaters

There are currently two classes of Fast Ethernet repeaters, defined as Class I and Class II .

Class I : in a maximum length segment topology, only one Class

Irepeater may exist between any two nodes within a single collision domain.

Class II : in a maximum length segment topology, two Class II repeaters may exist between any two nodes within a single collision domain.

Will 100BASE-TX run on Category 3 cable?

No! Category 3 (CAT 3) cabling even in short lengths generates too much near end crosstalk for 100BASE-TX networks. The IEEE 802.3u 100BASE-TX Fast Ethernet standard requires Category 5 100 Ω UTP or 150 Ω STP which complies with ISO/IEC 11801:1995.

What is Category 5?

Category 5 (CAT 5) is a further extension of the EIA/TIA-568 cabling system to 100 MHz. Category 5 components (i.e., UTP trunk and patch cables, modular plug, and patch panel, etc.) are defined by EIA/TIA-568, but with the characterizations extended to 100 MHz by TSB-36 and TSB-40. The cable grades are categorized as follows:

•Category 3: up to 16 MHz

•Category 4: up to 20 MHz.

•Category 5: up to 100 MHz.

KNE24TX/RS User’s Guide - Rev. A01 Kingston Technology Company