Modular connectors are the snap-latch system originally built for telephone wiring, now the global standard for Ethernet, telephone, and structured cabling interfaces. The 8P8C plug — universally called RJ45, though strictly that's the wiring standard rather than the physical connector — terminates every LAN port from 10BASE-T through 10GBASE-T.

The central design decision for Ethernet is where to put the magnetics. IEEE 802.3 requires isolation transformers and common-mode chokes between the PHY and the cable. These can sit as discrete components on the PCB with a plain RJ45 next to them, or they can be built into the connector itself. The integrated version — variously called a MagJack, ICM, or integrated connector module depending on the manufacturer — tightens up PCB layout considerably and takes the magnetics specification matching off your plate. The trade-off is unit cost and flexibility; if the PHY changes, you may need a different integrated module. At 10GBASE-T the magnetics requirements are more demanding, so check the PHY's reference design before committing to an integrated part.

Key variants: unmagnetised RJ45 for use with discrete transformers, integrated versions with magnetics and LED indicators for front-panel ports, POE-rated connectors with contacts specified for the current levels in 802.3af, 802.3at, and 802.3bt (up to 960mA per pair in 802.3bt), stacked and ganged housings for dense port panels, and IP67-sealed industrial versions for environments where the connector sees water or heavy particulate. 1000BASE-T uses all four pairs; 10/100BASE-T uses two — but the physical connector is identical across all three.

Selection comes down to: shielded or unshielded (shielded adds EMI performance in noisy industrial environments), integrated or discrete magnetics, port count per package, LED configuration for speed and link/activity indication, and POE current rating if power delivery is needed.

TRX sources Ethernet and modular connectors from Amphenol, Molex, TE Connectivity, and Bel Fuse through authorised distribution. No minimum order. In-stock lines ship to Johannesburg, Cape Town, Durban, and Pretoria. For parts that need to be sourced, we'll quote an actual lead time.

Send us your part number or describe the application — we'll come back with availability and pricing.