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Connectors and Interfaces FAQs

Connectors and interfaces decide what a system can plug into and how far a signal can travel. These FAQs explain the ports, cables and video interfaces you meet on industrial PCs, displays and capture cards: HDMI, DisplayPort, USB-C, BNC, SMA, RJ45, M12, serial and more.

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Topics 12
CONNECTORS · VIDEO

DisplayPort vs HDMI: What Is the Difference?

DisplayPort and HDMI both carry digital video and audio. DisplayPort, from VESA, is the computer-monitor standard, with a latching connector, daisy chaining and up to 80 Gb/s in version 2.1. HDMI is the TV and consumer standard, with CEC control and audio return. For a PC to monitor link either works, so match the ports you have.

6 MIN
CONNECTORS · VIDEO

What Is DVI?

DVI, Digital Visual Interface, is a video connection published by the Digital Display Working Group in 1999. It carries digital video, and on DVI-I connectors analog VGA video too. Single-link DVI reaches 1920 × 1200 at 60 Hz and dual-link 2560 × 1600. DVI has no audio in the standard and uses screw-locked connectors.

6 MIN
CONNECTORS · USB AND POWER

What Is USB-C?

USB-C is a small, reversible 24-pin connector defined by the USB Implementers Forum. It is a connector, not a speed: the same port can carry USB 2.0, USB 3.2 or USB4 data, DisplayPort video, Thunderbolt and up to 240 W of USB Power Delivery, depending on what the device and cable support.

6 MIN
CONNECTORS · VIDEO AND RF

What Is a BNC Connector?

A BNC connector is a coaxial connector with a quarter-turn bayonet lock. It carries video and radio-frequency signals over coax cable and comes in two impedances: 75 ohm for video such as SDI and CCTV, and 50 ohm for RF, test equipment and timing signals.

6 MIN
SERIAL COMMUNICATION · NETWORKING

What Is a Serial to Ethernet Converter?

A serial to Ethernet converter, also called a serial device server, connects an RS-232, RS-422 or RS-485 device to an Ethernet network. It carries the serial data inside TCP or UDP packets, so software on a remote computer can reach the device through a virtual COM port or a network socket instead of a local serial cable.

6 MIN
SERIAL COMMUNICATION · INTERFACES

What Is Baud Rate?

Baud rate is the number of signal changes, or symbols, a communication link sends per second. On RS-232, RS-485 and other UART serial links each symbol carries one bit, so 9600 baud means 9,600 bits per second. Both ends must use the same baud rate, or the data arrives garbled.

6 MIN
CABLES · ETHERNET

T568A vs T568B: What Is the Difference?

T568A and T568B are the two color codes for wiring an RJ45 plug or socket, both defined in the ANSI/TIA-568 cabling standard. The only difference is that the orange and green pairs swap places. Both perform identically; what matters is using the same scheme at both ends of a straight-through cable.

6 MIN
INDUSTRIAL I/O · VEHICLE NETWORKS

What Is CAN FD?

CAN FD (CAN with Flexible Data-rate) is the faster version of CAN bus. It carries up to 64 bytes of data per message instead of 8, and switches to a higher bit rate, typically 2 to 5 Mbit/s, for the data part of each frame. It uses the same two-wire bus and is standardized in ISO 11898-1.

6 MIN
GPUS AND AI · FORM FACTORS

SXM vs PCIe GPUs: What Is the Difference?

SXM and PCIe are two ways of fitting an NVIDIA data centre GPU. An SXM GPU is a module mounted flat on a server baseboard, with higher power and all-to-all NVLink between GPUs. A PCIe GPU is a standard add-in card for ordinary server slots that uses less power and links to other cards over PCIe or an NVLink bridge.

6 MIN
GPUS AND AI · INTERCONNECTS

What Is NVLink?

NVLink is NVIDIA’s high-speed link between GPUs. It lets two or more GPUs exchange data and share memory directly, at many times the bandwidth of PCI Express, so they can work on one large AI model or simulation. It runs over a bridge between PCIe cards or through NVSwitch chips on multi-GPU server boards.

6 MIN
INDUSTRIAL I/O · CONTROL SIGNALS

What Is PWM (Pulse Width Modulation)?

PWM (pulse width modulation) controls the power delivered to a load by switching a digital output fully on and off at a fixed frequency and varying the on-time, called the duty cycle. The load responds to the average, so PWM can set motor speed, LED brightness, valve position or heater output efficiently.

6 MIN
NETWORKING · ETHERNET STANDARDS

What Is 1000BASE-T?

1000BASE-T is Gigabit Ethernet over copper twisted pair: 1,000 Mb/s on all four pairs of Cat 5e or better cable, up to 100 m per link, defined in IEEE 802.3ab. In the IEEE naming scheme the number is the speed in Mb/s, BASE means baseband signaling and the suffix names the medium.

7 MIN
ENCLOSURES · CABLE ENTRY

What Is a Cable Gland?

A cable gland is a fitting that takes a cable through the wall of an enclosure and seals, grips and protects it at the point of entry. It keeps dust and water out to a stated IP rating and stops the cable being pulled loose. Some glands also earth cable armour or screens, or keep a hazardous-area enclosure safe.

6 MIN
EXPANSION · CABLED PCIE

What Is MCIO?

MCIO (Mini Cool Edge IO) is a compact internal connector and cable system that carries PCIe lanes from a motherboard to NVMe drive backplanes, riser cards and accelerators. Defined by SNIA as SFF-TA-1016, it comes in x4, x8 and x16 versions and is built for PCIe 5.0 and 6.0 signaling.

6 MIN
EXPANSION · PCI EXPRESS

What Is PCIe?

PCIe (PCI Express) is the high-speed serial interface that connects graphics cards, NVMe SSDs, network cards and other devices to a computer’s processor. Data travels over lanes, and slots come in x1, x4, x8 and x16 widths. Each PCIe generation roughly doubles the speed per lane.

6 MIN
INTERFACES · EXPANSION

What Is PCIe 6.0?

PCIe 6.0 is the sixth generation of PCI Express. It doubles PCIe 5.0’s rate to 64 GT/s per lane by switching to PAM4 signaling with fixed-size FLIT packets and forward error correction, giving about 121 GB/s in each direction on an x16 link. The specification was released in 2022 and the first hardware is reaching data-centre servers.

6 MIN
INTERFACES · EXPANSION

What Is PCIe 5.0?

PCIe 5.0 is the fifth generation of PCI Express, the link between a processor and its GPUs, NVMe SSDs and network cards. It runs at 32 gigatransfers per second per lane, about 3.9 GB/s in each direction, so an x16 slot carries roughly 63 GB/s each way. It is backwards compatible with earlier generations.

6 MIN
CONNECTORS · VIDEO

What Is HDMI CEC?

HDMI CEC (Consumer Electronics Control) is a control channel built into HDMI that lets connected devices send each other commands over the HDMI cable. It turns a TV on when a player starts, switches inputs and passes remote-control buttons along. TV makers give it their own names, such as Anynet+, SimpLink and Bravia Sync.

6 MIN
CONNECTORS · USB

USB 3.2 Gen 1 vs Gen 2: What Is the Difference?

USB 3.2 Gen 1 runs at 5 Gb/s and USB 3.2 Gen 2 at 10 Gb/s, so Gen 2 has twice the bandwidth. Gen 1 is the port first sold as USB 3.0, and Gen 2 was USB 3.1. Both work on USB-A and USB-C, and USB 3.2 Gen 2x2 doubles Gen 2 to 20 Gb/s on USB-C only.

6 MIN
EXPANSION · CARD FORMATS

What Is Mini PCIe?

Mini PCIe (mPCIe) is a small plug-in card format for embedded computers and laptops, defined by PCI-SIG in 2003. The 52-pin socket carries one PCIe lane and USB 2.0, plus a SIM interface for cellular modems. It is used for Wi-Fi, 4G modems, GNSS, serial, CAN and video capture cards in full-size and half-size versions.

6 MIN
CONNECTORS · RF AND ANTENNAS

What Is an MMCX Connector?

An MMCX connector is a micro-miniature coaxial connector that snaps on and can rotate a full 360 degrees once mated. It is usually 50 ohm, works from DC to around 6 GHz and is rated for around 500 mating cycles. It is used for GNSS, Wi-Fi and cellular leads inside compact equipment, on camera boards and on detachable earphone cables.

6 MIN
CONNECTORS · STORAGE

What Is a SATA Connector?

A SATA connector is the flat, L-shaped connector that links a hard drive or SSD to a motherboard. Each drive has two: a 7-pin data connector carrying the Serial ATA signal at up to 6 Gb/s, and a 15-pin power connector supplying 3.3, 5 and 12 V. eSATA is the shielded external version for outside drives.

6 MIN
CONNECTORS · AUTOMOTIVE RF AND CAMERAS

What Is a FAKRA Connector?

A FAKRA connector is an automotive coaxial connector: an SMB-type 50 ohm RF contact inside a colour-coded, keyed plastic housing that clicks and locks. Standardized in ISO 20860 and USCAR-18, it carries antenna signals such as GPS, cellular and radio, and is the usual connector on GMSL cameras for edge AI and vehicle vision systems.

6 MIN
CONNECTORS · SERIAL I/O

What Is a DB9 Connector?

A DB9 connector is the nine-pin, D-shaped connector used for RS-232 serial ports on computers and industrial equipment. Its correct name is DE-9, because the nine pins sit in the smaller E-size shell. The same connector also carries RS-422, RS-485 and CAN bus, so the pinout depends on the interface behind it.

6 MIN
CONNECTORS · VIDEO

How Long Can an HDMI Cable Be?

The HDMI specification sets no maximum length. In practice a good passive cable carries 1080p reliably to around 10 to 15 m, 4K at 60 Hz to around 5 m and 48 Gb/s HDMI 2.1 signals to around 2 to 3 m. Active and optical cables, extenders and AV over IP reach from tens of meters to kilometers.

6 MIN
CONNECTORS · VIDEO

What Is HDMI?

HDMI, short for High-Definition Multimedia Interface, is a digital connection that carries video, multichannel audio and control signals over one cable. Introduced in 2002, it is the standard input on TVs and most monitors. The version, from HDMI 1.4 to 2.1, sets the bandwidth, and the cable type must be certified for it.

6 MIN
CONNECTORS · RF AND ANTENNAS

What Is an SMA Connector?

An SMA connector is a small threaded 50 ohm coaxial connector for antennas and RF signals, typically rated from DC to around 18 GHz. It is the usual antenna connector on Wi-Fi, 4G, 5G and GNSS equipment. RP-SMA, its reverse-polarity version, swaps the centre pin and socket and is common on Wi-Fi antennas.

6 MIN
CONNECTORS · USB

What Is a USB Hub?

A USB hub turns one USB port into several, sharing that port’s bandwidth between the devices plugged into it. A bus-powered hub draws all its power from the computer’s port, while a powered hub has its own supply, so each port can deliver full USB current to drives, cameras and other demanding devices.

6 MIN
CONNECTORS · VIDEO

VGA vs HDMI: What Is the Difference?

VGA is an analog video connection with a 15-pin plug and no audio, while HDMI is digital and carries video, multichannel audio and control signals on one cable. HDMI gives a sharper picture at full HD and above and supports 4K and HDCP. VGA survives on industrial and legacy equipment because so many machines still use it.

5 MIN
CONNECTORS · USB

What Are the Types of USB Ports?

The main USB port types are USB-A, the flat rectangular port on computers; USB-B, the square port on printers and instruments; Mini-B and Micro-B on older small devices; and USB-C, the reversible oval port now replacing them. The connector shape is separate from the speed, which runs from 480 Mb/s on USB 2.0 to 40 Gb/s on USB4.

7 MIN
CABLES · ETHERNET

Cat6 vs Cat6A: What Is the Difference?

Cat6A is tested to 500 MHz against Cat6’s 250 MHz and adds limits on alien crosstalk between neighboring cables. That lets Cat6A carry 10GBASE-T the full 100 m, where Cat6 typically manages around 37 to 55 m. Cat6A is thicker and stiffer, so it suits backbone links, multi-gigabit access points and high-power PoE bundles.

6 MIN
CABLES · ETHERNET

Cat5e vs Cat6: What Is the Difference?

Cat5e is tested to 100 MHz and Cat6 to 250 MHz, with thicker conductors and tighter crosstalk limits. Both carry gigabit Ethernet and 2.5 Gb/s to 100 m. Cat6 adds 5 Gb/s to 100 m, 10 Gb/s over shorter runs and less heating with PoE, while Cat5e is thinner, cheaper and easier to pull through existing routes.

6 MIN
CONNECTORS · VIDEO

What Is VGA?

VGA, Video Graphics Array, is an analog video standard introduced by IBM in 1987. A VGA port uses a 15-pin D-sub connector that carries separate red, green and blue signals plus sync, with no audio. It is still common on industrial monitors and legacy machines, and connecting it to HDMI needs an active converter.

6 MIN
CONNECTORS · USB AND POWER

What Is USB4?

USB4 is the USB Implementers Forum’s data standard that runs at 20 or 40 Gb/s, or 80 Gb/s in USB4 Version 2.0, over a USB-C connector only. It is built on the Thunderbolt 3 protocol and can tunnel USB, DisplayPort video and PCIe traffic through one cable at the same time.

6 MIN
CABLES · ETHERNET AND FIELDBUS

What Is Twisted Pair Cable?

Twisted pair cable is cable in which two insulated conductors are twisted together, usually in several pairs under one jacket. The twist makes outside interference affect both wires equally, so a differential receiver cancels it. It is the cable behind Ethernet, telephone lines, RS-485 and CAN bus, in unshielded (UTP) and shielded (STP) forms.

6 MIN
CONNECTORS · ETHERNET

What Is RJ45?

RJ45 is the common name for the eight-pin modular connector used on Ethernet cables and network ports. Strictly it is an 8P8C connector, defined in IEC 60603-7 and wired to the T568A or T568B scheme, and it carries Ethernet data from 10 Mb/s to 10 Gb/s plus Power over Ethernet.

9 MIN
CONNECTORS · VIDEO

What Is HDCP?

HDCP, High-bandwidth Digital Content Protection, is an anti-copying system that encrypts video between a source and a display over HDMI, DisplayPort and DVI. Every device in the chain must authenticate before protected content plays. HDCP 2.2 and 2.3 are needed for most 4K content, and a non-compliant link shows a blank screen or HDCP error.

6 MIN
CABLES · VIDEO AND RF

What Is a Coaxial Cable?

A coaxial cable is a cable with a centre conductor, an insulating layer, a metal shield and an outer jacket, all sharing one axis. The shield keeps interference out and the signal in, so coax carries video, broadband and radio-frequency signals over long runs with low loss.

6 MIN
CONNECTORS · USB AND THUNDERBOLT

What Is a Thunderbolt Port?

A Thunderbolt port is a high-speed connection developed by Intel that carries data, video, PCIe and power through one cable. Since Thunderbolt 3 it uses the USB-C connector and is marked with a lightning bolt icon. Thunderbolt 4 runs at 40 Gb/s and Thunderbolt 5 at 80 Gb/s, with up to 120 Gb/s for displays.

6 MIN
INTERFACES · SERIAL AND COM PORTS

What Is a Serial Port?

A serial port is a computer interface that sends data one bit at a time over a single line in each direction. On PCs it usually means an RS-232 COM port on a nine-pin connector, and industrial computers also offer RS-422 and RS-485 serial ports for PLCs, sensors and instruments.

7 MIN
EXPANSION · PCIE

What Is a Riser Card?

A riser card is a small circuit board that plugs into a motherboard expansion slot and turns it through 90 degrees, so expansion cards sit parallel to the motherboard. It lets full-size PCIe cards, such as GPUs and network cards, fit in low-height cases like 1U and 2U rack servers and compact industrial PCs.

6 MIN
CONNECTORS · SERIAL, VIDEO AND I/O

What Is a D-Sub Connector?

A D-sub connector is a multi-pin connector with a D-shaped metal shell that only fits one way round. It comes in five shell sizes with 9 to 50 standard pins, and is used for RS-232 serial ports (DE-9, often called DB9), VGA video (DE-15) and parallel and I/O connections (DB25, DC-37).

6 MIN
CONNECTORS · USB AND THUNDERBOLT

Thunderbolt vs USB-C: What Is the Difference?

USB-C is a connector; Thunderbolt is an Intel interface that uses it. Thunderbolt 3, 4 and 5 run over USB-C ports and cables, so every Thunderbolt port is also a USB-C port. A plain USB-C port may run only USB 2.0 or USB 3.2, while Thunderbolt guarantees 40 Gb/s or more, PCIe and display support.

6 MIN
CONNECTORS · VIDEO

What Are the Different Monitor Connection Types?

The main monitor connection types are HDMI, DisplayPort and USB-C for current digital video, DVI for older digital equipment and VGA for analog. Industrial and broadcast monitors add SDI over BNC and composite video. HDMI and DisplayPort carry audio; VGA and DVI do not. The best choice is the newest connection both the computer and the monitor share.

6 MIN
INTERFACES · PORTS AND CONNECTORS

What Are Computer Ports?

Computer ports are the sockets on a computer that connect it to other devices: USB for peripherals, Ethernet for networks, HDMI and DisplayPort for displays, audio jacks, and on industrial PCs serial COM ports, digital I/O and CAN bus. Each port pairs a connector with an interface standard that sets its speed and purpose.

7 MIN
CABLES · ETHERNET

Cat5 vs Cat6: What Is the Difference?

Cat6 is tested to 250 MHz against Cat5e’s 100 MHz, with tighter twists and better crosstalk control. Both carry gigabit Ethernet to 100 m, but Cat6 also runs 10 Gb/s to around 55 m, while Cat5e tops out at 2.5 to 5 Gb/s. For a full 100 m at 10 Gb/s, use Cat6A.

6 MIN
DISPLAYS · USB-C

What Is DisplayPort Alt Mode?

DisplayPort Alt Mode is a VESA standard that sends a DisplayPort video signal through a USB-C connector. A computer with a supporting USB-C port can drive a monitor over one USB-C cable, which can also carry USB data, for touch, and power. Not every USB-C port supports it, so the host must be checked.

6 MIN
DISPLAYS · RACK MOUNT

What Is a KVM Switch?

A KVM switch lets one keyboard, video display and mouse control several computers. You switch between machines with a button, a keyboard hotkey or an on-screen menu, so a rack of servers or industrial PCs does not need a screen and keyboard for each one. A rack mount KVM console builds the switch, screen and keyboard into one drawer.

6 MIN
VIDEO · INTERFACES

HDMI 2.0 vs HDMI 2.1: What Is the Difference?

HDMI 2.1 raises the maximum bandwidth from 18 Gbps on HDMI 2.0 to 48 Gbps by switching to a new signaling method called Fixed Rate Link. That moves the ceiling from 4K at 60 Hz to 4K at 120 Hz and 8K at 60 Hz, and adds features such as variable refresh rate and enhanced audio return.

6 MIN
VIDEO · COMPARISON

SDI vs HDMI: What Is the Difference?

SDI and HDMI both carry uncompressed digital video, but for different settings. SDI runs over coaxial cable with locking BNC connectors and covers long distances, around 100 m for 3G-SDI, making it the standard in broadcast, defense and industry. HDMI is a consumer interface with short cables and push-fit connectors, common on monitors, PCs and cameras.

6 MIN
VIDEO · INTERFACES

HDMI 2.0 vs HDMI 1.4: What Is the Difference?

HDMI 2.0 raises the maximum bandwidth from 10.2 Gbps on HDMI 1.4 to 18 Gbps, which allows 4K video at 60 frames per second instead of 30. For video capture and AI on camera feeds, that means smoother 4K and more detail per second for the model to work with.

6 MIN
DEFENSE · CONNECTORS

What Is MIL-DTL-38999?

MIL-DTL-38999 is the US military specification for high-density, environmentally sealed circular connectors. It defines four series of connector, with bayonet, threaded and breech-lock coupling, used for power, signal and data on aircraft, military vehicles and rugged computers.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is an M12 L-Coded Connector?

An M12 L-coded connector is an M12 power coding for DC supplies, rated up to 16 A at 63 V and defined in IEC 61076-2-111. It is used mainly to distribute 24 V power to PROFINET devices and field I/O, replacing larger 7/8 inch power connectors, and has 4 or 5 contacts.

6 MIN
RUGGED COMPUTING · CONNECTORS

Which M12 Codings Are Used for Power?

M12 power connectors use dedicated codings. L and T coding carry DC power, up to 16 A and 12 A at 63 V; S and K coding carry AC power up to 630 V. The older C coding was used for AC sensors and power. Low-current DC supplies, such as many computers’ power inputs, often use A coding.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is an M12 A-Coded Connector?

An M12 A-coded connector is the most common M12 coding, used for sensors, actuators, low-voltage DC power and general signals. It has a single key and comes with 3, 4, 5, 8 or 12 pins, defined in IEC 61076-2-101. On industrial computers, A-coded connectors carry DC power input, serial ports, USB and digital I/O.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is an M12 B-Coded Connector?

An M12 B-coded connector is the M12 coding reserved for PROFIBUS fieldbus networks. It usually has 5 pins and a key on the opposite side to A coding, so a fieldbus cable cannot be connected to a sensor or power port by mistake. It is defined in IEC 61076-2-101.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is an M12 D-Coded Connector?

An M12 D-coded connector is the 4-pin M12 coding for 10/100 Mbps Ethernet. It is used for PROFINET, EtherNet/IP, EtherCAT and many rail and vehicle networks. Pins 1 and 3 carry the transmit pair and pins 2 and 4 the receive pair. It is defined in IEC 61076-2-101.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is an M12 X-Coded Connector?

An M12 X-coded connector is the 8-pin M12 coding for Gigabit and 10 Gigabit Ethernet. Its four twisted pairs are separated by a cross-shaped shield that controls crosstalk at high speed, and it can carry Power over Ethernet with a suitable cable. It is defined in IEC 61076-2-109.

6 MIN
RUGGED COMPUTING · CONNECTORS

How Do You Connect M12 to RJ45?

An M12 Ethernet port connects to an RJ45 network with an M12 to RJ45 cable or adaptor that matches the port’s coding. A 4-pin D-coded M12 carries 10/100 Mbps Ethernet on RJ45 pins 1, 2, 3 and 6; an 8-pin X-coded M12 carries Gigabit and faster Ethernet on all eight RJ45 pins.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is the Difference Between M8 and M12 Connectors?

M8 and M12 are circular industrial connectors named after their thread: 8 mm and 12 mm. M8 is smaller, with 3 to 8 pins, and suits compact sensors and low-power signals. M12 is larger, with up to 12 pins and more codings, and carries higher power and Ethernet up to 10 Gbit/s, which is why industrial computers use it.

6 MIN
RUGGED COMPUTING · CONNECTORS

What Is M12 Coding?

M12 coding is the key and pin layout inside an M12 connector that stops incompatible plugs and sockets being mated. Each coding has a job: A for sensors and DC power, B for PROFIBUS, D and X for Ethernet, and L, T, S and K for power. A plug only fits a socket with the same coding.

7 MIN
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