A guide to 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/IP™, 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/IP̢㢠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 Through 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 patch 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. Twisting 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 can't 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 another 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