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  CommServ > Infrastructure > Standards > History > EIA/TIA-568 and TSB-36

The EIA/TIA-568 wiring standard recognizes four (4) cable types and two (2) telecommunications outlets. These standards are implemented in two specific configurations at UCSB. Listed below are summaries of the relevant cable standards and their implementation in the UCSB wiring standard. For simplicity, references to measurement standards are indicated by ". . ." and not detailed.

From EIA/TIA-568 reference page 10, Section 4.4 (Global Engineering Documents).

There are four types of cables that are recognized in the horizontal wiring system. These cables include:

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Four-Pair 100 Ohm Unshielded Twisted Pair (UTP) Cables

The cable consists of 24 AWG thermoplastic insulated conductors formed into four individually twisted pairs and enclosed by a thermoplastic jacket.

Note 1: Four-pair, 22 AWG cables which meet the transmission requirements of this section may also be used.

Note 2: Four-pair, shielded twisted pair cables which meet the transmission requirements of this section may also be used. The mechanical and physical specifications are a subject for future study.

Note 3: For some LAN applications a higher grade medium may be required.

Insulated Conductor

The diameter over the insulation shall be 1.22 mm (0.048 in) max.

Pair Assembly

The pair twists of any pair shall not be exactly the same as any other pair. The pair twist lengths shall be selected by the manufacturer to assure compliance with the crosstalk requirements of this standard.

Color Codes

Pair 1	White-Blue   (W-BL)*	Blue (BL)"
Pair 2	White-Orange (W-O)* 	Orange (O)"
Pair 3	White-Green  (W-G)* 	Green (G)"
Pair 4	White-Brown  (W-BR)*	Brown (BR)"
* (Wire insulation is white and a colored marking is added)
" (A white marking is optional)

Cable Diameter

The diameter of the completed cable shall be less than 6.35mm (0.25 in)

Breaking Strength

The ultimate breaking strength of the completed cable . . . 90 lb minimum.

Note: The maximum pulling tension should not exceed 25 lb to avoid stretching.

Bending Radius

The cable tested . . . shall withstand a bend radius of 25.4 mm (1 in) at a temperature of -20 C without jacket or insulation cracking

Transmission Requirements

DC Resistance

The resistance of any conductor, measured . . . , shall not exceed 28.6 ohms per 305 m (1000 ft) at or corrected to a temperature of 20 C.

DC Resistance Unbalance

The resistance unbalance between the two conductors of any pair shall not exceed 5% when measured at or corrected to a temperature of 20 C in . . . .

Mutual Capacitance

The mutual capacitance of any pair at 1 kHz, measured . . . , shall not exceed 20 nF per 305 M (1000 ft) at or corrected . . . .

TSB Enhanced Definition for Mutual Capacitance

The mutual capacitance of any pair at 1 kHz and measured at or corrected at a temperature of 20C, shall not exceed 17 nF per 305 m (1000 ft) for category 4 and category 5 cables.

Capacitance Unbalance: Pair to Ground

The capacitance unbalance to ground at 1 kHz of any pair, measured . . . , shall not exceed 1000 pF per 305 m (1000 ft) at or corrected . . . .


The attenuation of any pair, measured or corrected . . . , shall not exceed the following values:

Frequency 	Max Attenuation
(MHz)       (db/1000')
 0.064	        2.8
 0.256	        4.0
 0.512        	5.6
 0.772	        6.8
 1.0            7.8
 4.0           17
 8.0           26
10.0           30
16.0           40

TSB Enhanced Definition for Maximum Attenuation

The maximum attenuation of any pair shall be less than the values given in the following table in the frequency range for 0.772 MHz to the highest referenced frequency.

Maximum Attenuation dB per 1000 ft @ 20C

Frequency  Category 3     Category 4	  Category 5

 0.064          2.8	        2.3	       2.2
 0.256	        4.0	        3.4	       3.2  
 0.512	        5.6	        4.6	       4.5
 0.772          6.8       	5.7	       5.5
 1.0	        7.8          	6.5            6.3
 4.0          	17	         13          	13
 8.0	        26  	         19	        18
10.0          	30	         22	        20
16.0          	40               27        	25
20.0	         -	         31  	        28
25.0           	-          	-          	32
31.25          	-          	-	        36
62.5           	-          	-               52
100            	-          	-          	67

Characteristic Impedance

The characteristics impedance, when measured according to . . . , shall meet the following requirements:

Frequency (MHz)		Characteristic Impedance (ohms)
     0.064               125 +/- 15%
     0.128               115 +/- 15%
     0.256               110 +/- 15%
     0.772               102 +/- 15%
   1.0 - 16.0            100 +/- 15%

TSB Enhanced Definition for Characteristic Impedance

Both category 4 and category 5 cables shall have a characteristics impedance of 100 Ohms +/- 15% in the frequency range from 1 MHz up to the highest referenced frequency.

NOTE: The method of measuring "characteristic impedance" is currently under study by the industry. As a result of structural non-uniformities, the measured input impedance for an electrically long length of cable will fluctuate as a function of frequency. This fluctuation is related to the Structural Return Loss (SRL) for a cable that is terminated in its own characteristic. Generally, the Enhanced Unshielded Twisted Pair (EUTP) cables in categories 4 and 5 provide improved SRL performance.

Near-End Crosstalk (NEXT)

The NEXT coupling loss between any two pairs within a cable, tested in . . . , shall be equal to or greater than the following values:

Frequency (MHz)		NEXT Loss Worst Pair ( db @ 1000 ft)
    0.15                     54
    0.772                    43
    1.0                      41
    4.0                      32
    8.0                      28
   10.0                      26
   16.0                      23

TSB Enhanced Definition for NEXT Loss

The NEXT value at 0.772 MHz shall be 43 dB for category 3 cable, 58 dB for category 4 cable and 64 dB for category 5 cable.

The following table gives values of worst pair NEXT Loss at specific frequencies in the band of interest.

Frequency  Category 3  Category 4     Category 5

  0.150       54         	68           74
  0.772       43         	58           64
  1.000       41         	56           62
  4.000       32         	47           53
  8.000       28         	42           48
 10.000       26         	41           47
 16.000       23         	38           44
 20.000        -         	36           42
 25.000        -                 -           41
 31.250        -                 -           40
 62.500        -                 -           35
100.000        -                 -           32

NOTES: The NEXT Loss of patch cable shall be equivalent to the NEXT loss of equal length of horizontal cable over the range of frequencies specified for any given cable category. The NEXT Loss for connectors should be better than the NEXT values for any given cable category specified above.

Measurement Precaution

The transmission measurements of mutual capacitance, capacitance unbalance, characteristic impedance, attenuation, and NEXT shall be performed on cable samples removed from the reel or packages. The test sample shall be stretched along a non-conduction surface or supported in aerial spans such that there is a minimum 1.0 in separation between any convolutions.

Note 1: On reel measurement is prohibited because parameters in Mutual Capacitance and Attenuation can be up to 10% higher for cables measured on spools.

Note 2: When installed on a ground plant, metallic conduit, or other conducting surface, the parameters of Mutual Capacitance and Attenuation may be higher and the parameters of Attenuation may be lower.

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Two-Pair 150 Ohm Unshielded Twisted Pair (UTP) Cables

The cable shall meet the requirements of EIA Interim Standard Omnibus Specification, NQ-EIQ/IS-43 (Ref B1.9) and the following detail specifications:

 Specification and Cable Type     Intended Application

 (1) NQ-EIA/IS-43AB (Ref B1.11)   Not for use in plenum areas

 (2) NQ-EIA/IS-43AC (Ref B1.12)   Not for use in plenum areas
                                  May be used between floors

 (3) NQ-EIA/IS-43AD (Ref B1.13)   Not for use in plenum areas
                                  May be used between floors

 (4) NQ-EIA/IS-43AE (Ref B1.14)   For use in non-plenum areas

 (5) NQ-EIA/IS-43AF (Ref B1.15)   Not for use in plenum areas
                                  May be used between floors

 (6) NQ-EIA/IS-43AG (Ref B1.16)   For jumper and patch cord 
                                  applications only

UCSB Implementation Notes

UCSB Communications Services has used the IBM Type-2 cable specification for workstation communications. This cable consists of four unshielded twisted pairs as defined in the EIA-568 standard, but also includes two shielded twisted pairs and a stranded shield surrounding all cable pairs.

This cable was first used in 1975 well before the introduction of standards in unshielded twisted pair processing. Because the university continues to demonstrate the need for higher speeds over twisted pair, and manufacturer research continues in the implementation of 100 Megabit speeds over copper (CDDI) in both unshielded and shielded cables, the use of Type-2 combination cable is continued.

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50-Ohm Coaxial Cable

The cable shall meet the specifications defined in IEEE 802.3 (10BASE2) (Ref B1.4).

UCSB Implementation Notes

The coaxial cable defined in the IEEE 802.3 is widely used on the university campus. However, it is expected that future use of this cable will be reduced and eventually eliminated. New building or major re-modeling will NOT provide for this cable, but will instead provide the unshielded and shielded twisted pair listed above.

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Fiber Optic Cable - 62.5/125 um (10.2.4)

There are three parts to the specification for fiber optic cable:

Optical Fiber Specifications

The fiber shall be multimode, graded-index optical fiber waveguide with nominal 62.5/125um core/cladding diameter. The fiber shall comply with ANSI/EIA/TIA-492AAAA (Ref B1.18).

Cable Transmission Performance Specifications

Each cabled fiber shall meet the graded performance specifications below:

Wavelength   Maximum Attenuation   Minimum Information 
   (nm)            (dB/km)         Transmission Capacity
    850             3.75           160
   1300             1.50           500

Attenuation shall be measured in accordance with EIA fiber optic test procedures EIA/TIA-455-46, -61, or -53 (Ref B.1.39). Information transmission capacity shall be measured in accordance with the following EIA/TIA-455-51 or -30 (Ref B1.39). The cable shall be measured at 25 degrees C. +/- 5 degrees C.

Physical Cable Specifications

The mechanical and environmental specifications for indoor fiber optic cable shall be in accordance with ANSI/ICEA S-83-596 (Ref B1.40).

Telecommunications Outlet Specification

100-ohm UTP Cable

Each four-pair cable shall be terminated in an eight-position modular jack in the work area. The 100-ohm UTP telecommunications outlet shall meet the requirements described in EIA/TIA-570 (Ref. B1.2) and EIA/TIA-TSB-31 (Ref B1.37).

UCSB Implementation Notes

UCSB Communications Services terminates the four unshielded twisted pairs on two (2) jacks - one RJ-11 for voice and one RJ-45 for data (10BaseT). This is done to streamline the attachment of modular cables for voice and data devices without the use of eight-wire Y cables to access two sets of two pairs.

150 Ohm STP Cable

The telecommunications connector used for terminating the 150-ohm STP cable shall be that specified by ANSI/IEEE 802.5 (Ref B1.5)v for the media interface connector. This connector shall be hermaphroditic in design so that identical units will mate when oriented 180 degrees with respect to each other.

UCSB Implementation Notes

The two shielded twisted pairs (STP) contained in the Type-2 cable sheath are terminated on a separate RJ-45 connector. The specification as written calls for a hermaphroditic connector such as the IBM Token-Ring connector. IBM now supports token-ring using the RJ-type connector.


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Last modified: 10/19/2007