- Generic

Glossary

Category 5 cable UTP (Unshielded twisted pair)

A multi-pair (usually 4 pair) high performance cable that consists of twisted pair conductors and is used mainly for data transmission. The twisting of the pairs gives the cable a certain amount of immunity from the infiltration of unwanted interference. The basic Cat 5 cable was designed for characteristics of up to 100 MHz and is typically used for Ethernet networks running at 10 or 100 Mbps.

 

Category 5e cable (enhanced)

This is the same as the Cat5 (above), except that it is made to somewhat more stringent standards (see comparison chart below). The Cat5e standard is now officially part of the 568A standard. Cat5e is recommended for all new installations and was designed for transmission speeds of up to 1 gigabit per second (Gigabit Ethernet).

 

Category 6 cable

This is the same as the Cat5e, except that it is made to a higher standard (see comparison chart below). The Cat6 standard is now officially part of the 568A standard.

 

Category 7 cable

This cable is the same as the Cat6, except that it is made to a higher standard (see comparison chart below). The Cat7 standard is still in the works (as of time of writing) and is not yet part of the 568A standard. One major difference with Cat7’s construction (as compared with Cat5, 5e and 6) is that all four pairs are individually shielded and an overall shield enwraps all four pairs. Cat 7 will use an entirely new connector (other than the widely-used RJ-45).

 

Category 5 cable SCTP (screen twisted pair)

Same as above, except that the twisted pairs are given additional protection from unwanted interference by an overall shield. There is some controversy concerning which is the better system; UTP or SCTP. Cat5 SCTP cabling systems require all components to maintain the shield and are used almost exclusively in European countries.

 

Category 5E RJ45 (Work Area Outlet)

An 8 conductor, compact, modular, female jack that is used to terminate cat5e cables at the user (or other) location. The jack is specifically engineered to maintain the performance of Cat5e cabling.

 

Category 5e patch panel

A Cat5e patch panel is basically just a series of many cat5e jacks condensed into a single panel. Common panel configurations are 12, 24, 48 and 96 ports. Patch panels are typically used where all of the horizontal cable sections meet and are used to connect the segments to the Network Hub.

 

Category 5e patch cable

A Cat5e patch cable consists of a length of Cat5e cable with an RJ-45 male connector crimped onto each end. The cable assembly is used to provide connectivity between any two Cat5e female outlets (jacks). The two most common are from hub to patch panel, and work area outlet (jack) to the computer.

 

EIIA/TIA 568A Standard

This standard was published in July 1991. Its purpose was to create a multi-product, multi-vendor standard for connectivity.

 

568A and 568B wiring schemes

When we refer to a jack or patch panel’s wiring connection, we refer to either the 568A or 568B wiring scheme, which dictates the pin assignments to the pairs of Cat5e cable. It is very important to note that there is no difference, whatsoever, between the two wiring schemes, in connectivity or performance when connected form one long modular device to another (jack or patch panel) so long as the two devices are wired to the same scheme (A or B). The only time when one scheme has an advantage over the other, is when one end of a segment is connected to a modular device and the other end to a punch block – in which case the 568A has the advantage of having a more natural progression of pairs at the punch block side.

 

Four Pairs

Pair 1: White/Blue

Pair 2: White/Orange

Pair 3: White/Green

Pair 4: White/Brown

 

Wiremap

This is the most basic test that can be performed on a Cat5e segments and tests for the basic continuity between the two devices. In 568A or B all eight pins of each device should be wired straight through (1 to 1, 2 to 2, 3 to 3, etc.). A wiremap (continuity) test should also test for absence of shorts, grounding, and external voltage.

 

Crosstalk

Crosstalk is the “bleeding” of signals carried by one pair onto another pair through the electrical process of induction (wires need not make contact as signals are transferred magnetically). This is an unwanted effect that can cause slow transfer or completely inhibit the transfer of date signals over the cable segment. The purpose of the wire twists is to significantly reduce the crosstalk and its effects. Two types are: NEXT (Near End Crosstalk) and FEXT (Far End Crosstalk). (N.B. Fibre optic cable is the only medium that is 100% immune to the effects of crosstalk.)

 

Ambient Noise or electromagnetic interference (EMI)

Similar to crosstalk in that it is an unwanted signal that is induced into the cable. The difference is that ambient noise (or EMI) is typically induced from a source that is external to the cable. This could be an electrical cable or device, or even an adjacent Cat5e cable.

 

Attenuation

This is the loss of the signal in a cable segment due to the resistance of the wire plus other electrical factors that cause additional resistance (e.g. impedance and capacitance). A longer cable length, poor connections, bad insulation, a high level of crosstalk or ambient noise will all increase the total level of attenuation. The 568A standard specifies the maximum amount of attenuation that is acceptable in a cat5e cable segment.

 

Category 5,5e, 6 and 7 performance specification chart

 

Parameter
Cat5 & Class D
(with additional requirements TS895 & FDAM 2)
Cat5e
(568-A-5)
Cat6 Class E
(Performance 250MHz shown in brackets)
Proposed Cat7 Class F
(Performance at 600MHz shown in brackets)
Specified           frequency             range
1-100MHz 1-100Mhz 1-250MHz 1-600MHz
Attenuation
24 dB 24 dB 21.7dB
(36 dB)
20.9 dB
(54.1 dB)
NEXT
27.1dB 30.1dB 39.9db
(33.1dB)
62.1dB
(51dB)
ACR
3.1dB 6.1dB 18.2dB
(-2.9dB)
41.3dB
(48dB)
Power-sum           ACR
N/A 3.1dB 15.4dB
(-5.8dB)
38.3dB
(-6.1dB)**
Power-sum NEXT
N/A* 27.1dB 37.1dB
(30.2dB)
59.1dB
(48dB)
ELFEXT
17 dB (new requirement) 17.4 dB 23.2dB
(15.3dB)
Ffs***
Return loss
8 dB (new requirement) 10 dB 12dB (8db) 14.1dB
(8.7dB)
Propagation delay
548 nsec 548 nsec 548 nsec
(546 nsec)
504 nsec
(501 nsec)
Delay skew
50 nsec 50 nsec 50 nsec 20 nsec