Ethernet Cables

Where do the terms Cat5 and Cat5e come from ?

TIA Telecommunications Industry Association, TIA defined standard TIA-568-B which defines the cables and structured or modular cabling systems and termination standards for building and telecom cabling systems.

Cat5 and Cat5e Cable – What is the difference?

  • Very simply put – The 5e cable is tested to a higher standard. A manufacturer may produce a single cable and only test some of it to the 5e standard. The physical characteristics of the cable are no different but the Cat5e’s higher specification makes it suitable for Gigabit Ethernet.
  • Whilst we are on the subject – what about Cat6 ? Bandwidth is 2.5 greater at 250MhZ and that’s probably the limit with RJ45 connectors. You might be future proofing using this cable but you could also be wasting money. Also remember that Cat6 is a high tech cable and requires connectors and patch cables assembled to meet the standard.

  Category 5 Category 5e
Frequency 100 MHz 100 MHz
Attenuation (Min. at 100 MHz) 22 dB 22 dB
Characteristic Impedance 100 ohms ± 15% 100 ohms ± 15%
NEXT (Min. at 100 MHz) 32.3 dB 35.3 dB
PS-NEXT (Min. at 100 MHz) no specification 32.3 dB
ELFEXT (Min. at 100 MHz) no specification 23.8 dB
PS-ELFEXT (Min. at 100 MHz) no specification 20.8 dB
Return Loss (Min. at 100 MHz) 16.0 dB 20.1 dB
Delay Skew (Max. per 100 m) no specification 45 ns

Source : discountcablesusa.com

Below are comparisons of two cables – one a Cat5 and the other Cat5e.

Cat5e Cable Example

Part Number: 11700A Paired – Category 5e DataTuff® Twisted Pair Cable

DESCRIPTION:

24 AWG Bonded-Pairs solid bare copper conductors, polyolefin insulation, PVC inner jacket, rip cord, industrial grade sunlight- and oil-resistant PVC outer jacket. Sequential marking at two foot intervals.

SUITABLE APPLICATIONS :

Suitable Applications: Industrial Ethernet Cable, Harsh Environments, EtherNet/IPâ„¢, 350MHz Enhanced Category 5e, Gigabit Ethernet, 100BaseTX, 100BaseVG ANYLAN, 155ATM, 622ATM, NTSC/PAL Component or Composite Video, AES/EBU Digital Audio, AES51, RS-422, CMX – Outdoor, RJ-45 Compatible, Extra Protection

PHYSICAL CHARACTERISTICS :

    CONDUCTOR :
    Number of Pairs: 4
    Total Number of Conductors: 8
    AWG: 24
    Stranding: Solid
    Conductor Diameter: .020 in.
    Conductor Material: BC - Bare Copper
    INSULATION :
      Insulation Material: PO - Polyolefin
      Nom. Insulation Wall Thickness: .009 in.
      Insulation Diameter: .035 in.
      Pair Color Code Chart:
   Number  Color
    1  White/Blue Stripe & Blue
    2  White/Orange Stripe & Orange
    3  White/Green Stripe & Green Number  Color
    4  White/Brown Stripe & Brown
   INNER JACKET :
      Inner Jacket Material: PVC - Polyvinyl Chloride
      Inner Jacket Diameter: .200 in.
      Inner Jacket Ripcord: Yes
   OUTER SHIELD :
      Outer Shield Material: Unshielded
      OUTER SHIELD SEPARATOR :
      Outer Shield Separator Thickness: 0.001 in.
   OUTER JACKET :
      Outer Jacket Material: Industrial Grade PVC - Polyvinyl Chloride
      Outer Jacket Nominal Wall Thickness: .035 in.
      Outer Jacket Ripcord: Yes
      OVERALL NOMINAL DIAMETER :
      Overall Nominal Diameter: .285 in.
   MECHANICAL CHARACTERISTICS :
      Operating Temperature Range: -40°C To +75°C
      Storage Temperature Range: -40°C To +85°C
      Installation Temperature Range: -25°C To +75°C
      Bulk Cable Weight: 35 lbs/1000 ft.
      Max. Recommended Pulling Tension: 40 lbs.
      Min. Bend Radius (Install): 0.29 in.
   APPLICABLE SPECIFICATIONS AND AGENCY COMPLIANCE :
      APPLICABLE STANDARDS :
      NEC/(UL) Specification: CMR, CMX-Outdoor, UL444
      CEC/C(UL) Specification: CMR
      IEC Specification: 11801 Category 5
      EU RoHS Compliant (Y/N): Yes
      EU RoHS Compliance Date (mm/dd/yyyy):: 01/01/2004
      PMSHA Specification: P-07-KA060005
      TIA/EIA Specification: 568-B.2 Category 5e
      Other Specification: NEMA WC-63.1 Category 5e, Ethernet/IPâ„¢ compliant, UL verified to Category 5e
      FLAME TEST :
      UL Flame Test: UL1666 Riser
      CSA Flame Test: FT4
   SUITABILITY :
      Suitability - Indoor: Yes
      Suitability - Outdoor: Yes
      Sunlight Resistance: Yes
      Oil Resistance: Yes
   PLENUM/NON-PLENUM :
      Plenum (Y/N): N
   ELECTRICAL CHARACTERISTICS :
      Nom. Mutual Capacitance @  pF/ft
      Maximum Capacitance Unbalance (pF/100 m): 66 pF/100 m
      Nominal Velocity of Propagation: 70 %
      Maximum Delay (ns/100 m): 510 ns/100 m
      Maximum Delay Skew (ns/100m): 25 ns/100 m
      Maximum Conductor DC Resistance @ 20 Deg. C: 9 O/100 m
      Maximum DCR Unbalance @ 20 Deg. C: 3 %
      Max. Operating Voltage - UL: 300 V RMS
   ELECTRICAL CHARACTERISTICS - PREMISE :
      Premise Cable Electricals Table 1:
      Frequency (MHz)  Max. Attenuation (dB/100 m)  Min. NEXT (dB)  Min. PSNEXT (dB)  Min. ACR (dB)  Min. PSACR (dB)  Min. Return Loss (dB)  Min. Structural Return Loss (dB)
       1               2.0   65.3  65.3  63.3  63.3      20.0
       4               4.0   56.3  56.3  52.3  52.3      23.0
       8               5.7   51.8  51.8  46.1  46.1      24.5
       10              6.4   50.3  50.3  43.9  43.9      25.0
       16              8.1   47.3  47.3  39.1  39.1      25.0
       20              9.2   45.8  45.8  35.2  35.2      25.0
       25              10.3  44.3  44.3  34.1  34.1      24.3
       31.25           11.6  42.9  42.9  31.3  31.3      23.6
       62.5            16.8  38.4  38.4  21.6  21.6      21.5
       100             21.7  35.3  35.3  17.1  17.1      20.1
       155             27.7  32.5  32.5  4.7    4.7      19.0
       200             32.0  30.8  30.8  3.0    3.0       19.0
       250             36.4  29.3  29.3  >0  >0           18.0
       300             40.5  28.2  28.2  >0  >0           18.0
       310             41.3  27.9  27.9                   18.0
       350             44.3  27.2  27.2                   17.0
   Premise Cable Electricals Table 2:
   Frequency (MHz)  Input (Unfitted) Impedance (O)  Fitted Impedance (O)  Min. ELFEXT (dB)  Min. PSELFEXT (dB)
       1               100 ± 12  105 ± 10  63.8  60.8
       4               100 ± 12  100 ± 10  51.7  48.7
       8               100 ± 12  100 ± 10  45.7  42.7
       10             100 ± 12  100 ± 10  43.8  40.8
       16             100 ± 12  100 ± 10  39.7  36.7
       20             100 ± 12  100 ± 10  37.7  34.7
       25             100 ± 15  100 ± 10  35.8  32.8
       31.25        100 ± 15  100 ± 10  33.9  30.9
       62.5          100 ± 15  100 ± 10  27.8  24.8
       100           100 ± 15  100 ± 10  23.8  20.8
       155           100 ± 18  100 ± 10  19.9  16.9
       200           100 ± 20  100 ± 10  17.7  14.7
       250           100 ± 20  100 ± 10  15.8  12.8
       300           100 ± 20  100 ± 10  14.2  11.2
       310           100 ± 20  100 ± 10  13.9  10.9
       350           100 ± 22  100 ± 10  12.9  9.9


Cat5 Cable Example

Part Number: 1633A Paired – Category 5 Unbonded-Pair Cable

DESCRIPTION:
24 AWG solid bare copper conductors, non-plenum, Polyolefin insulation, twisted pairs, overall Beldfoil® Shield, drain wire, rip cord, see color code chart (below), PVC jacket (gray or blue).
 SUITABLE APPLICATIONS :
Suitable Applications: Premise Horizontal Cable
PHYSICAL CHARACTERISTICS :
CONDUCTOR :
Number of Pairs: 4
Total Number of Conductors: 8
AWG: 24
Stranding: Solid
Conductor Material: BC - Bare Copper  

INSULATION :
Insulation Material:
- Polyolefin
>Pair Color Code Chart:  

Number  Color
 1  White/Blue Stripe & Blue
 2  White/Orange Stripe & Orange
 3  White/Green Stripe & Green
 4  White/Brown Stripe & Brown

OUTER SHIELD :
Outer Shield Material Trade Name: Beldfoil®
Outer Shield Type: Tape
Outer Shield Material: Aluminum Foil-Polyester Tape
Outer Shield %Coverage: 100 %  

OUTER SHIELD DRAIN WIRE :
Outer Shield Drain Wire AWG: 24
Outer Shield Drain Wire Stranding: Solid
Outer Shield Drain Wire Conductor Material: TC - Tinned Copper  

OUTER JACKET :

Outer Jacket Material: PVC - Polyvinyl Chloride
Outer Jacket Ripcord: Yes  

OVERALL NOMINAL DIAMETER :
Overall Nominal Diameter: .260 in.  

MECHANICAL CHARACTERISTICS :  

Operating Temperature Range: -20°C To +80°C
Bulk Cable Weight: 28 lbs/1000 ft.
Max. Recommended Pulling Tension: 25 lbs.
Min. Bend Radius (Install): 1 in.  

APPLICABLE SPECIFICATIONS AND AGENCY COMPLIANCE :  

APPLICABLE STANDARDS :
NEC/(UL) Specification: CM, UL444
CEC/C(UL) Specification: CM  

EU CE Mark (Y/N): Yes
EU RoHS Compliant (Y/N): Yes
EU RoHS Compliance Date (mm/dd/yyyy):: 01/01/2004
TIA/EIA Specification: 568 TSB 36, Category 5
Other Specification: UL verified to TSB 36, Category 5  

FLAME TEST :
UL Flame Test: UL1685 UL Loading
CSA Flame Test: FT1
PLENUM/NON-PLENUM :
Plenum (Y/N): N  

ELECTRICAL CHARACTERISTICS :  

Nom. Mutual Capacitance @  pF/ft
Maximum Capacitance Unbalance (pF/100 m): 330 pF/100 m
Nominal Velocity of Propagation: 67 %
Maximum Delay (ns/100 m): 538 @ 100MHz ns/100 m
Maximum Delay Skew (ns/100m): 45 ns/100 m
Maximum Conductor DC Resistance @ 20 Deg. C: 9.38 O/100 m
Maximum DCR Unbalance @ 20 Deg. C: 5 %
Max. Operating Voltage - UL: 300 V RMS
ELECTRICAL CHARACTERISTICS - PREMISE :
Premise Cable Electricals:  

Frequency (MHz)  Max. Attenuation (dB/100 m)  Min. NEXT (dB)  Min. PSNEXT (dB)  Min. Structural Return Loss (dB)  Fitted Impedance (Ohms)
 1         2.0       62.3  No Spec  No Spec  100 ± 15%
 4         4.1       53.3  No Spec  No Spec  100 ± 15%
 8         5.8       48.8  No Spec  No Spec  100 ± 15%
 10       6.5       47.3  No Spec  No Spec  100 ± 15%
 16       8.2       44.3  No Spec  No Spec  100 ± 15%
 20       9.3       42.8  No Spec  No Spec  100 ± 15%
 25       10.4     41.3  No Spec  No Spec  100 ± 15%
 31.25  11.7     39.9  No Spec  No Spec  100 ± 15%
 62.5    17.0     35.4  No Spec  No Spec  100 ± 15%
 100     22.0     32.3  No Spec  No Spec  100 ± 15%

Straight Thru Patch Cable vs Cross-Over Cable

The easiest way to tell the difference is to take the two ends and gold them up against each other. If the same color wires on are the same pins it’s a straight through path cable. If any of them cross-over then it’s a ….. cable.

Ethernet Cable Color Coding

There are two color coding standards. The color coding standard does not affect whether the cable is a cross-over or straight through patch cable. Color does not affect performance or use of the cable.

Standard 568A  

Standard 568B

This is the most commonly used for patch cables.

1 White-Green   1 White-Orange
2 Green   2 Orange
3 White-Orange   3 White-Green
4 Blue   4 Blue
5 White-Blue   5 White-Blue
6 Orange   6 Green
7 White-Brown   7 White-Brown
8 Brown   8 Brown
         

Why twist the pairs ?

Signals can bleed or crosstalk from one pair to another. Twsisting significantly reduces the degree of crosstalk.

Near End Cross Talk is known as NEXT

Far End Cross Talk is known as FEXT

Ethernet Cables and RJ45 Connectors

It is often recommended that the RJ45 connector match the cable – If the cable is stranded the use a RJ45 plug with stranded conductors. The author cant find a reason for this assertion.

The standard for the use of RJ45 connectors on cat5 and Cat5e cable is a maximum untwist of 0.5inch for termination on the RJ45 connector.

Under no circumstances should an other part of the cable be unwound. Take great care in assembling cables and inspect the assembly if the cable doesn’t perform well.

Stranded vs Solid Conductors

The use of stranded conductors is recommended for flexible cables like patch cable. There is some discussion suggesting that solid conductors offer slightly better performance over the life of the cable.

© Chipkin Automation Systems 2007