UK What a NIC does
A NIC, or network interface card, is the hardware that links a computer to a network. The same part is also called a network interface controller, a network adapter or a LAN adapter. Whatever the name, it sits between the computer’s processor and the cable or radio link, and nothing reaches the network without passing through it.
A wired NIC has two main parts. The controller, or MAC, builds outgoing data into Ethernet frames, checks incoming frames and moves them to and from memory over the PCIe bus. The PHY turns those frames into electrical or optical signals on the cable. In networking terms, the NIC works at layer 1 (physical) and layer 2 (data link); the operating system’s TCP/IP stack and drivers handle everything above.
Every NIC carries a 48-bit MAC address, set at the factory, whose first half identifies the manufacturer through an IEEE-assigned prefix. Switches use that address to deliver frames to the right port, which is why a computer with two NICs has two MAC addresses.
Types of NIC
NICs differ in how they connect to the computer and which network they join. Most computers have at least one built in, and further NICs are added for more ports, higher speeds or a different medium.
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Onboard NIC. A controller soldered to the motherboard with an RJ45 port on the rear panel, often called LAN on motherboard. Industrial boards commonly carry two to five.
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PCIe NIC. An expansion card with one to four ports, used for extra ports, 10GbE and faster links, fibre or PoE output to cameras.
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M.2 and mini PCIe NICs. Small modules that add Ethernet to compact boards with no full-size PCIe slot, usually with a cable to a panel connector.
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USB network adapter. A NIC in a dongle. Convenient for laptops and servicing, but less suited to permanent installations because of the connector and USB latency.
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Wireless NIC. A Wi-Fi or Wi-Fi and Bluetooth module, usually M.2 in current systems, with antenna leads to the enclosure.
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SmartNIC or DPU. A data-centre NIC with its own processor that offloads tasks such as storage, encryption or virtual switching from the host.
NIC speeds and cabling
Ethernet speeds are defined by the IEEE 802.3 standards, and the NIC, the cable and the switch must all support the same speed. Copper NICs negotiate down automatically, so a 2.5GbE port still works on a Gigabit network.
| Speed | IEEE standard | Medium | Typical reach | Typical use |
|---|---|---|---|---|
| 1 Gb/s (1000BASE-T) | 802.3ab | Cat5e copper, RJ45 | 100 m | Controllers, office PCs, most IP cameras |
| 2.5 Gb/s (2.5GBASE-T) | 802.3bz | Cat5e copper, RJ45 | 100 m | Edge computers, Wi-Fi 6 access points |
| 5 Gb/s (5GBASE-T) | 802.3bz | Cat6 copper, RJ45 | 100 m | Multi-camera vision, faster uplinks |
| 10 Gb/s (10GBASE-T) | 802.3an | Cat6a copper, RJ45 | 100 m (around 55 m on Cat6) | Servers, storage, high-resolution cameras |
| 10 Gb/s (SFP+) | 802.3ae | Fibre or direct-attach copper | Around 300 m multimode, 10 km single-mode | Long runs, noisy sites, backbones |
| 25 Gb/s (SFP28) | 802.3by | Fibre or direct-attach copper | Depends on optic | Edge AI servers, data centres |
Fibre NICs take plug-in SFP transceivers, so the same card can use multimode, single-mode or copper modules depending on the run.
Features that matter in industrial NICs
On a desktop, the NIC is rarely a decision. In industrial and edge systems, the controller and the card around it decide whether cameras get power, clocks stay in step and the link survives the site.
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PoE output. Cards with power sourcing ports (IEEE 802.3af, at or bt) power GigE Vision and IP cameras over the same cable. Our Ethernet and PoE frame grabbers are NICs built for this job.
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Hardware timestamping. Controllers with IEEE 1588 PTP support timestamp packets in hardware, so cameras and sensors share a clock to within microseconds. See our guide to synchronising machine vision with PTP.
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Time-sensitive networking. Controllers such as Intel’s I210 and I226 add scheduling features from the IEEE 802.1 TSN standards for deterministic traffic. Our TSN guide explains when it matters.
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Offloads and queues. Checksum and segmentation offload, receive-side scaling and multiple queues keep processor load down when several cameras stream at once.
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Environment. Wide temperature ratings, surge protection, isolated ports and locking M12 connectors for vehicles, rail and outdoor cabinets.
Onboard NIC or add-in card
The onboard NIC is enough for most connections. An add-in card is worth it when you need more ports than the board has, PoE, 10GbE or fibre, separate interfaces to keep an OT network apart from the office network, or a specific controller for PTP or driver support. Our PCIe LAN and PoE expansion cards cover Gigabit to 10GbE in industrial temperature versions.
A NIC is not a switch. A NIC gives one computer more network interfaces, while an Ethernet switch gives the network more ports and forwards traffic between devices. A multi-port NIC does not switch traffic between its ports unless the operating system is set up to bridge them.
Quick answers on NICs
NICs: common questions
What does NIC stand for?
Network interface card, or network interface controller. Both mean the same hardware. In UK payroll and tax, NIC usually means National Insurance contributions instead.
Does every computer have a NIC?
Almost every one. Desktops, laptops and industrial computers have at least one built in, wired, wireless or both. A few sealed or air-gapped designs leave it out on purpose.
Are NIC cards still used?
Yes. Onboard NICs cover basic needs, but add-in cards remain the way to get extra ports, 10GbE and faster, fibre or PoE output.
Is a network adapter the same as a NIC?
Yes. Network adapter, LAN adapter, Ethernet card and NIC all describe the same thing. Windows lists them under network adapters.
How do I find my NIC’s MAC address?
Ask the operating system. On Windows, run ipconfig /all and read the physical address. On Linux, run ip link. Each NIC port has its own address.
We fit and configure the NICs in every industrial and edge computer we supply as standard, including PoE cards, fibre modules and drivers, and validate each port before the system ships.