Communications Cables Revised: 04.08.00
Transmission Categories Reason for Revision: Show publication of CAT 5e; Add "CAT 7"; editorial additions to paragraph 1

In response to the growing demand for data applications, cable performance evolved such that there are currently 6 levels, called Categories, of transmission performance for Unshielded Twisted Pair (UTP) cables that are defined by US standards. Two additional levels of performance are in the process of being standardized. These are detailed in the table below. The levels are hierarchical. In other words, a higher category can be substituted for any lower category.

Category Maximum Bandwidth Application Specifications Comments
7 > 500 MHz probably will be close to 1 GHz 1000BaseT w/extra EMI protection Under consideration Shielded Twisted Pair comparable to IEC 11801 Class F
6 250 MHz 1000BaseT Under development Specs ready mid-year 2000 at earlest. Patch cords are an issue.
5e 100 MHz Same as CAT 5 plus 1000BaseT TIA/EIA 568-A-5 Published October 1999
5 100 MHz 1000BaseT*

100 Mbps TPDDI (ANSI X 319.5)

155 Mbps ATM

TIA/EIA 568-A (Category 5)

NEMA (Extended Frequency)

ANSI/ICEA S-91-661

Characterized by tightly twisted pairs to reduce crosstalk loss. Plenum versions are expensive due to demanding transmission requirements combined with challenging flame/smoke resitance. Some manufacturers are offering a CMX rated CAT 5 for residences.
4 20 MHz 10 Mbps Ethernet (IEEE 802.3)

16 Mbps Token Ring (IEEE 802.5)

TIA/EIA 568-A (Category 4)

NEMA (Extended Distance)

ANSI/ICEA S-91-661

Almost non-existent. So similar to Category 5 that it is not economical. CAT 5 gives you 5 times the bandwidth for about the same cost.
3 16 MHz 10 Mbps Ethernet (IEEE 802.3) TIA/EIA 568-A (Category 3)

NEMA (Standard Loss)

ANSI/ICEA S-91-661

Widely used for voice, especially digital voice, installations in commercial sites. Market trend is to abandon CAT 3 in favor of installing CAT 5 for both data and voice.
2 4 MHz IBM Type 3

1.544 Mbps T1

1 Base 5 (IEEE 802.3)

4 Mbps Token Ring (IEEE 802.5)

IBM Type 3

ANSI/ICEA S-91-661

ANSI/ICEA S-80-576

Requirements based on the IBM cabling system. Referred to as a low-speed data cable. Not a big item in the market.
1 < 1 MHz POTS (Plain Old Telephone Service)

RS 232 & RS 422

ISDN Basic Rate

ANSI/ICEA S-80-576

ANSI/ICEA S-91-661

Good only for analog voice. Conductorized (quad) station wire fits this category. OK for doorbells.

*Only if additional requirements of TIA/EIA TSB 95 are met.

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