Handbook for Sound Engineers

Transmission Techniques: Wire and Cable 413

Category 1. Meets the minimum requirements for ana-
log voice or plain old telephone service (POTS). This
category is not part of the EIA/TIA 568 standard.

Category 2. Defined as the IBM Type 3 cabling sys-
tem. IBM Type 3 components were designed as a higher
grade 100: UTP system capable of operating 1 Mb/s
Token Ring, 5250, and 3270 applications over short-
ened distances. This category is not part of the EIA/TIA
568 standard.

Category 3. Characterized to 16 MHz and supports
applications up to 10 Mbps. Cat 3 conductors are
24 AWG. Applications range from voice to 10Base-T.

Category 4. Characterized to 20 MHz and supports
applications up to 16 Mb/s. Cat 4 conductors are
24 AWG. Applications range from voice to 16 Mbps
Token Ring. This category is no longer part of the
EIA/TIA 568 standard.

Category 5. Characterized to 100 MHz and supports
applications up to 100 Mbps. Cat 5 conductors are
24 AWG. Applications range from voice to 100Base-T.
This category is no longer part of the EIA/TIA 568 stan-
dard.

Category 5e. Characterized to 100 MHz and supports
applications up to 1000 Mbps/1 Gbps. Cat 5e conductors
are 24 AWG. Applications range from voice to
1000Base-T. Cat 5e is specified under the TIA standard
ANSI/TIA/EIA-568-B.2. Class D is specified under ISO
standard ISO/IEC 11801, 2nd Ed.

Category 6. Characterized to 250 MHz, in some ver-
sions bandwidth is extended to 600 MHz, and supports
1000 Mbps/1 Gbps and future applications and is back-
ward compatible with Cat 5 cabling systems. Cat 6 con-
ductors are 23 AWG. This gives improvements in power
handling, insertion loss, and high-frequency attenuation.
Fig. 14-4 shows the improvements of Cat 6 over Cat 5e.
Cat 6 is specified under the TIA standard
ANSI/TIA/EIA-568-B.2-1. Class E is specified under
ISO standard ISO/IEC 11801, 2nd Ed. Cat 6 is available
most commonly in the United States as UTP.

Category 6 F/UTP. Cat 6 F/UTP (foiled unshielded
twisted pair) or ScTP (screened twisted pair) consists of
four twisted pairs enclosed in a foil shield with a
conductive material on one side. A drain wire runs adja-
cent to the conductive side of the shield, Fig. 14-5.
When appropriately connected, the shield reduces
ANEXT, RFI, and EMI. Cat 6 FTP can only be
designed to 250 MHz per TIA/EIA 568B.2-1.

Category 6a. Cat 6a (Augmented Category 6) is charac-

terized to 500 MHz, and in special versions to 625 MHz,

has lower insertion loss, and has more immunity to

noise. Cat 6a is often larger than the other cables.

10GBase-T transmission uses digital signal processing

(DSP) to cancel out some of the internal noise created by

NEXT and FEXT between pairs. Cat 6a is specified

under the TIA standard ANSI/TIA/EIA 568-B.2-10.

Class EA is specified under ISO standard ISO/IEC

11801, 2nd Ed. Amendment 1. Cat 6a is available as

UTP or FTP.

Category 7 S/STP. Cat 7 S/STP (foil shielded twisted-

pair) cable is sometimes called PiMF (pairs in metal

foil). Shielded-twisted pair 10GBase-T cable dramati-

cally reduces alien crosstalk. Shielding reduces electro-

magnetic interference (EMI) and radio-frequency

interference (RFI). This is particularly important as the

airways are getting more congested. The shield reduces

signal leakage and makes it harder to tap by an outside

source. Shield termination at 14.16 Class F will be speci-

fied under ISO standard ISO/IEC 11801, 2nd Ed. Class

FA will be specified under ISO standard ISO/IEC 11801,

2nd Ed. Amendment 1.

14.9.3.6.4 Comparisons

Table 14-17 compares network data rates for Cat 3

through Cat 6a and Table 14-18 compares various char-

acteristics of Cat 5e, 6, and 6a. Fig. 14-6 compares the

Figure 14-4. Normalized comparison of Cat 5e and Cat 6.

Figure 14-5. Cat 6 F/UTP.

Bandwidth Loss NEXT

2.5

2.0

1.5

1.0

0.5

0.0

Normalized value

Cat 5

Cat 6

Drain wire

Cable jacket

Foil shield

Source: BICSI