A
Alien Crosstalk (AXT) |
Electromagnetic interference that occurs between two separate cables running in close proximity, as opposed to crosstalk within a single cable. Alien crosstalk becomes a significant factor in Cat6a and above installations where multiple cables are bundled together in high-density pathways. It is one of the primary reasons Cat6a shielded (F/UTP or S/FTP) cable is specified for high-density runs. See also: NEXT, FEXT, Crosstalk |
Attenuation |
The reduction in signal strength as it travels along a cable. Measured in decibels (dB) per 100 metres. Higher frequency signals attenuate more quickly than lower frequency signals. Excessive attenuation causes data errors and network performance degradation. All Category cable standards specify maximum attenuation limits at defined frequencies. On the spec sheet: Shown as Insertion Loss (dB/100m at specified frequency, e.g. 100MHz). |
AWG (American Wire Gauge) |
A standardised wire sizing system used throughout the data cabling industry. Counterintuitively, a lower AWG number indicates a thicker (larger diameter) conductor. Cat6 cable typically uses 23 AWG conductors, while Cat6a uses 23 AWG. Cat5e uses 24 AWG. Thicker conductors have lower resistance and handle PoE power delivery more effectively over longer distances. Common values: 22 AWG (thicker, lower resistance), 23 AWG (Cat6/Cat6a standard), 24 AWG (Cat5e standard), 26–28 AWG (thin patch cords). |
B
Bandwidth |
The range of frequencies a cable can support, measured in MHz. Higher bandwidth allows higher data transmission speeds. Cat5e supports up to 100MHz, Cat6 up to 250MHz, Cat6a up to 500MHz, and Cat8 up to 2000MHz. Bandwidth and data rate (Gbps) are related but not the same: a 250MHz Cat6 cable supports 10 Gigabit Ethernet only up to 55 metres, while Cat6a at 500MHz supports 10 Gigabit to the full 100 metres. |
BNC Connector |
Bayonet Neill–Concelman connector. A coaxial cable connector with a quarter-turn bayonet locking mechanism. Widely used for video signal connections in analogue CCTV systems (RG59, RG6) and some test and measurement equipment. The bayonet lock provides a secure connection that resists accidental disconnection. |
C
CCA (Copper Clad Aluminium) |
A cable conductor type consisting of an aluminium core with a thin copper coating. CCA cable does not comply with AS/CA S008 and is illegal for customer cabling installations in Australia. Aluminium has approximately 60% higher electrical resistance than pure copper, causing excessive voltage drop in PoE applications and creating a fire risk under high current loads. Always specify and verify pure copper (OFC) cable. See also: The Dangers of CCA Cable |
Category Standards (Cat5e, Cat6, Cat6a) |
Performance classifications for twisted pair cabling defined by TIA-568 (USA) and ISO/IEC 11801 (international), adopted in Australia via AS/CA S008. Each category defines minimum performance requirements for bandwidth, attenuation, crosstalk, and return loss. Cat5e supports Gigabit Ethernet to 100m. Cat6 supports 10 Gigabit to 55m. Cat6a supports 10 Gigabit to the full 100m channel. |
Channel |
The complete end-to-end cabling link from switch port to device, including the patch cord at the switch, the permanent link (wall cabling), and the patch cord at the device. The Channel test standard is the most lenient of the three IEC/TIA test levels because it averages the performance across all components including patch cords. Maximum channel length is 100 metres. See also: Permanent Link, Component Test |
Continuous Voltage Rating |
The maximum voltage a cable or component can safely handle during normal, ongoing operation throughout its service life. On the spec sheet: Often shown as Uo/U (e.g., 0.6/1kV), where Uo is the voltage between conductor and earth, and U is the voltage between conductors. A typical value for PoE-rated Cat cable is 60V. |
Crosstalk |
Electromagnetic interference between adjacent wire pairs within the same cable. The twisting of pairs at different rates within the cable jacket is the primary method of controlling crosstalk. Higher twist rates provide better crosstalk rejection. Measured as Near End Crosstalk (NEXT) and Far End Crosstalk (FEXT). |
D
dB (Decibel) |
A logarithmic unit used to express the ratio of two signal levels. Used throughout cabling specifications to measure attenuation, crosstalk, and return loss. In cable testing, a positive dB headroom value means the cable exceeded the minimum standard (pass). A negative value means it fell short (fail). A 3dB difference represents a doubling or halving of signal power. |
Dielectric Withstand Voltage |
A manufacturing stress test that verifies the quality and durability of a cable's insulation. The cable is subjected to a high voltage (e.g., 1000V DC) for a short period (e.g., one minute) to confirm the insulation is free from defects, pinholes, or weak spots. On the spec sheet: Shown as a test value (e.g., |
Drip Loop |
A deliberate downward loop in a cable run at a wall penetration or equipment entry point. The loop ensures that water running along the outside of the cable drips off the lowest point of the loop rather than following the cable into the building or enclosure. A mandatory best practice for any outdoor cable entry. |
E
EMI (Electromagnetic Interference) |
Unwanted electrical noise generated by motors, fluorescent lighting, power cables, and other electrical equipment that interferes with data signal transmission. Shielded cable (F/UTP, S/FTP) provides protection against EMI by containing signals within the shield and preventing external interference from affecting the twisted pairs. See also: Cable Shielding Guide |
F
FEXT (Far End Crosstalk) |
Crosstalk measured at the far end of the cable from the signal source. FEXT measures the interference a transmitting pair causes on an adjacent pair at the receiving end. Equal Level Far End Crosstalk (ELFEXT) is the more meaningful measurement as it accounts for the attenuation of the interfering signal over the cable length. |
F/UTP |
Foiled Unshielded Twisted Pair. A cable construction where all four twisted pairs are wrapped together inside a single overall foil shield (the F/ prefix), but each individual pair is unshielded (the UTP suffix). Provides good EMI protection for general commercial environments. Less expensive and easier to terminate than individually shielded cables. Also known as: FTP, overall screened UTP. See also: Cable Shielding Guide |
G
Gas-Tight Crimp |
A crimp termination that deforms both the connector pin and the copper conductor to create a sealed joint that excludes oxygen. Preventing oxygen contact at the connection point eliminates corrosion at the interface, which would otherwise increase contact resistance over time and cause intermittent connection failures. A gas-tight crimp requires a precision ratchet crimp tool with correctly sized dies. |
H
Headroom (Test Margin) |
The difference in dB between a cable's measured performance and the minimum required by the standard. Positive headroom means the cable exceeded the standard (pass). Negative headroom means the cable failed. High headroom indicates better quality cable and a more robust installation with more tolerance for future degradation or additional connections. Example: A headroom of +4.5dB on a NEXT measurement means the cable performed 4.5dB better than the standard required. |
I
IDC (Insulation Displacement Contact) |
A termination method used in patch panels, wall plates, and Krone blocks where the conductor is pushed into a slotted contact that cuts through the insulation to make an electrical connection. IDC terminations do not require stripping the wire before termination. The slot width is precisely matched to the conductor diameter to ensure reliable contact. Requires a punch-down tool for correct seating. |
Insertion Loss |
The total signal loss from one end of a cable or connector to the other, measured in dB. The formal term for what is commonly called attenuation in a completed channel. A lower insertion loss value indicates better performance. Insertion loss increases with cable length and frequency. |
Insulation Resistance |
A measure of how effectively a cable's insulation prevents electrical signals from leaking between conductors or to the outside environment. Measured in megohm-kilometres (MΩ·km). A higher number is better. A value of 5000 MΩ·km indicates very high-quality insulation with minimal signal loss over long distances. |
IP Rating |
Ingress Protection rating. A two-digit code under AS 60529 that indicates how well an electrical enclosure or device resists intrusion from solid objects and liquids. The first digit (0–6) rates protection against solids; the second digit (0–9K) rates protection against liquids. IP65 is the standard minimum for exposed outdoor electrical equipment in Australian conditions. See also: IP Ratings Guide |
J
Jacket (Cable Jacket) |
The outer protective sheath of a cable. Jacket material determines suitability for the installation environment. PVC (polyvinyl chloride) is standard for indoor use. PE (polyethylene) or LSZH/PE blends are specified for outdoor use due to UV resistance. LSZH (Low Smoke Zero Halogen) jackets are required in confined spaces such as air plenums, ducts, and some commercial fit-outs where toxic smoke from a fire would be dangerous. |
L
LSZH (Low Smoke Zero Halogen) |
A cable jacket material that, when burned, produces minimal smoke and no halogenic gases. Standard PVC jackets produce toxic chlorine and hydrogen chloride gas when burned. LSZH jackets are specified for installations in air plenums, raised floor spaces, confined areas, and buildings where occupant safety during a fire is critical. Required by some building codes and specifications for data centre and commercial fit-out applications. |
M
Minimum Bend Radius |
The tightest radius a cable can be bent without kinking, damaging its internal twisted pairs, or degrading signal performance. Bending tighter than this limit permanently damages the cable. Two values apply: During installation (cable under tension, e.g., 52mm) and after installation (final resting position, e.g., 26mm). Cat6a has a larger minimum bend radius than Cat6 due to its thicker jacket. |
MHz (Megahertz) |
A unit of frequency equal to one million cycles per second. Used to specify cable bandwidth. Cat5e is rated to 100MHz, Cat6 to 250MHz, Cat6a to 500MHz. Higher MHz ratings allow the cable to carry higher-frequency signals, supporting faster data rates at longer distances. |
N
NEXT (Near End Crosstalk) |
Crosstalk measured at the same end of the cable as the signal source. When a pair is transmitting, it induces interference into adjacent pairs at the near end. NEXT is typically the most significant crosstalk measurement in data cabling as it directly affects the receiving signal on adjacent pairs. Measured in dB: a higher (more positive) value indicates better isolation between pairs. |
O
OFC (Oxygen Free Copper) |
Pure copper with oxygen content reduced to less than 0.001%. OFC provides lower electrical resistance, better conductivity, and greater resistance to corrosion than standard copper. Required for compliant customer cabling in Australia under AS/CA S008. The term "pure copper" is used interchangeably in the industry. See also: CCA, The Dangers of CCA Cable |
Operating Voltage |
The maximum voltage a cable is rated to carry safely throughout its service life. Critical for PoE applications. A cable rated at 30V is not suitable for PoE++ (Type 3 and 4) which operates at up to 52V or 57V. Always verify operating voltage when specifying cable for high-power PoE installations. Common values: 30V (basic PoE compatible), 60V (PoE++ Type 3 and 4 compatible). |
P
Patch Cord |
A short, factory-terminated cable used to connect equipment to a patch panel port or wall plate, or to connect between ports within a rack. Patch cords use stranded conductors (more flexible than solid conductors) and are rated for multiple insertions. Component-rated patch cords are tested individually to the TIA-568 standard. Channel-rated cords are only tested as part of a complete link. |
PE (Polyethylene) |
A cable jacket material with excellent UV resistance and moisture resistance, making it the standard choice for outdoor and direct burial cable applications. PE is harder and less flexible than PVC. It does not have the low-smoke properties of LSZH and is not suitable for indoor use in confined spaces. |
Permanent Link |
The fixed cabling installed within a building, from the patch panel at the telecommunications room to the wall plate at the work area. The Permanent Link test measures this fixed infrastructure only, excluding the patch cords at either end. It is the standard test performed by registered cablers certifying a structured cabling installation. Maximum length: 90 metres (leaving 10 metres allowance for patch cords in a 100-metre channel). |
PoE (Power over Ethernet) |
A technology defined under IEEE 802.3 that delivers DC electrical power alongside data over standard network cabling. PoE eliminates the need for separate power supplies at remote devices. Defined in multiple standards: 802.3af (Type 1, up to 15.4W), 802.3at (Type 2, up to 30W), 802.3bt Type 3 (up to 60W), and 802.3bt Type 4 (up to 90W at the PSE, up to 71.3W at the PD). See also: PSE, PD, Voltage Drop |
PSE / PD |
PSE (Power Sourcing Equipment) is the device that supplies power over the Ethernet cable: typically a PoE switch or PoE injector. PD (Powered Device) is the device that receives power: typically an IP camera, access point, VoIP phone, or access control reader. The power available at the PD is always less than what the PSE supplies due to resistance losses in the cable. |
PVC (Polyvinyl Chloride) |
The most common cable jacket material for indoor data cable. PVC is flexible, cost-effective, and suitable for general indoor installation environments. It is not UV-resistant and degrades outdoors. When burned, PVC releases toxic chlorine gas, making it unsuitable for plenum or confined space applications where LSZH cable is required. |
R
RCM (Regulatory Compliance Mark) |
The mandatory compliance mark for electrical and electronic products sold in Australia and New Zealand. Jointly owned by ACMA and the state electrical safety regulators. Replaces the former A-Tick and C-Tick marks. Confirms the product meets applicable electrical safety (EESS) and electromagnetic compatibility (ACMA) standards. See also: Product Compliance Guide |
Return Loss |
A measure of how well a cable's impedance is matched along its length. When a signal encounters a change in impedance, some of the signal is reflected back towards the source. This reflected energy is the return loss. Poor return loss (low dB value) causes data errors and limits cable performance at higher speeds. Caused by cable damage, poor terminations, or inconsistent manufacture. |
RJ45 |
An 8-position 8-contact (8P8C) modular connector used for Ethernet network connections. The "RJ45" designation is technically informal (RJ45 is a specific wiring configuration for telecommunication use), but it is universally used in the industry to refer to the standard network plug and socket. Available in standard, shielded, and keystone versions for different installation types. |
S
S/FTP |
Screened Foiled Twisted Pair. A cable construction where each individual twisted pair is wrapped in its own foil shield (the /FTP suffix) AND all four pairs are enclosed within an overall braided screen (the S/ prefix). Provides the highest level of EMI protection and alien crosstalk rejection. Specified for high-density Cat6a runs, data centres, and industrial environments with significant EMI. See also: Cable Shielding Guide |
Solid vs Stranded Conductor |
Solid conductors (one solid wire per conductor) are used in permanently installed structured cabling. They provide better electrical performance over long runs but are less flexible and will crack if repeatedly flexed. Stranded conductors (multiple thin wires twisted together per conductor) are used in patch cords. More flexible and resistant to repeated bending but slightly higher resistance. Never use stranded cable for permanent building installations. |
Split Pair |
A wiring fault where conductors from two different twisted pairs are incorrectly matched as a pair. For example, wiring pin 1 with the blue wire and pin 2 with the green wire (rather than the blue pair). A split pair will pass a basic continuity test because all eight pins are connected, but it will fail at high data rates because the unmatched conductors have no crosstalk cancellation. Only detected by a tester that checks pair mapping, not just pin connectivity. |
T
TDR (Time Domain Reflectometer) |
A test instrument that sends a signal pulse along a cable and measures the time and magnitude of reflected pulses to identify faults and measure cable length. TDR functionality is built into most professional cable certifiers and many LCD cable testers. It can locate the exact distance to a break, short circuit, impedance mismatch, or crushed section of cable without needing access to the far end. |
TIA-568 |
Telecommunications Industry Association standard for structured cabling systems. TIA-568.2-D is the current standard for balanced twisted-pair cabling. Defines performance requirements for each Category of cable, connector, and channel. Referenced in Australian standard AS/CA S008 and widely used as the basis for cable certification testing with Fluke and similar instruments. |
Twisted Pair |
Two insulated copper conductors twisted together in a helical pattern. The twisting causes electromagnetic interference from external sources to affect both conductors equally, allowing the differential signal to cancel out the interference. Each pair in a network cable is twisted at a different rate (twist rate) to minimise crosstalk between pairs. |
U
UTP (Unshielded Twisted Pair) |
Network cable with no metallic shield around the pairs or the cable as a whole. UTP relies entirely on the twist rates of each pair for crosstalk rejection. Easier to terminate and less expensive than shielded cable. Suitable for most standard office and commercial installations where EMI levels are low. Not recommended for industrial environments or runs alongside power cables. See also: Cable Shielding Guide |
Uo/U (Voltage Rating) |
A cable voltage rating format where Uo is the rated voltage between any conductor and earth (screen or ground), and U is the rated voltage between any two conductors. For example, a cable rated 0.6/1kV can safely carry 600V between any conductor and earth, and 1000V between conductors. For data cabling, the relevant voltage rating is the operating voltage for PoE applications. |
V
Voltage Drop |
The reduction in voltage along a cable caused by the resistance of the conductors. In PoE installations, voltage drop is the primary limiting factor for cable run length, not data transmission distance. High-power PoE devices (30W+) on long cable runs using standard Cat6 may receive insufficient voltage to operate reliably. Solutions include using Cat6a (lower resistance conductors), shorter runs, or PoE extenders. See also: Low Voltage Power Drop Charts |
W
Wire Map |
A cable test that verifies each conductor is connected to the correct pin at both ends and that no shorts, opens, crossed pairs, or split pairs exist. Wire map testing is the most basic level of cable verification and is performed by all cable testers from simple LED blinkers to professional certification units. A wire map pass does not confirm performance; it only confirms correct physical connections. |