When you specify an RJ45 jack — the female modular socket (母座) that the cable plug mates into — one of the first board-level decisions is how it attaches to the PCB: through-hole (THT) or surface-mount (SMT). The choice quietly drives mechanical robustness, assembly cost, board density and field reliability. This guide compares the two for RJ45 jacks specifically, with parameters sourced from IEC 60603-7, ANSI/TIA-568, IEEE 802.3 and IPC J-STD-020, and shows where VOOHU's jack range fits.
A through-hole (THT) RJ45 jack has solder tails (and usually metal board-lock pegs) that pass through plated holes in the PCB and are soldered on the opposite side, typically by wave or selective soldering. The barrel of each plated hole grips the lead, so mechanical loads are carried in shear by the board itself. This is why the classic sink-type integrated-magnetics jack — VOOHU's 1×1, 1×N and 2×N modules in 90° and 180° vertical mounts — is overwhelmingly through-hole.
A surface-mount (SMT) RJ45 jack terminates on pads on the board surface and is soldered in the same reflow pass as the rest of the assembly. It removes the routing-blocking holes from inner layers and suits fully automated pick-and-place lines, but each joint relies on pad adhesion, so SMT jacks add through-hole or SMT board locks to carry the plug-in force the solder pads alone should not.
| Attribute | Through-Hole (THT) | Surface-Mount (SMT) |
|---|---|---|
| Attachment | Solder tails + board-lock pegs inserted into plated holes, soldered on far side | Terminations soldered to surface pads; board locks added for strength |
| Solder process | Wave or selective soldering (or hand) | Reflow, in the main SMT pass (J-STD-020 profile, up to ~260 °C peak) |
| Mechanical strength under mating force | Highest — load carried through the board barrel | Lower at the joint; depends on board locks + pad adhesion |
| PCB density / routing | Holes consume inner-layer routing area; single-sided placement near the part | Frees inner layers; supports denser, double-sided layouts |
| Assembly fit | Adds a wave/selective step if the board is otherwise all-SMT | One reflow pass; lowest touch labor at volume |
| Rework | Robust joints; multi-pin desolder is laborious | Hot-air reworkable, but watch pad lift and lock damage |
| Typical RJ45 use | Front-panel jacks, integrated magjacks (sink-type), industrial & PoE, harsh environments | Low-profile internal jacks, space-constrained boards, high-volume consumer lines |
Mounting style is mechanical: the contact system sets the electrical class. An 8P8C RJ45 jack carries the same core ratings whether THT or SMT. The values below are the connector-class figures you can cite and verify; confirm the exact number on the part datasheet.
| Parameter | Typical value | Source / standard |
|---|---|---|
| Durability (mating cycles) | ≥ 750 cycles | IEC 60603-7 |
| Current rating per contact | 1.5 A | IEC 60603-7 |
| Contact resistance | ≤ 20 mΩ | IEC 60603-7-class datasheets |
| Insulation resistance | ≥ 500 MΩ | IEC 60603-7-class datasheets |
| Dielectric withstanding (jack) | 1000 V AC, 1 min | IEC 60603-7-class datasheets |
| Isolation, integrated magnetics (magjack) | 1500 V rms | IEEE 802.3 |
| Contact plating (mating area) | Gold over nickel — e.g. 6 / 15 / 30 / 50 µin (0.15 / 0.38 / 0.76 / 1.27 µm) | Industry plating tiers |
| Category bandwidth | Cat5e 100 MHz · Cat6 250 MHz · Cat6A 500 MHz | ANSI/TIA-568 |
| Operating temperature | −40 to +85 °C (industrial); 0 to +70 °C (commercial) | VOOHU integrated RJ45 range |
| Reflow peak (SMT parts) | up to ~260 °C | IPC J-STD-020 |
µin = microinch; 1 µin = 0.0254 µm. Heavier gold (30–50 µin) is chosen for high-cycle or corrosive service; thinner gold (6–15 µin) suits cost-sensitive indoor use. See our materials & plating guide for the full trade-off.
VOOHU Electronics manufactures RJ45 jacks / female modular sockets (母座) — not plugs or patch cables — including standard RJ45, low-profile (low-height), offset and combination jacks, plus integrated-magnetics (magjack) sink-type modules in 1×1, 1×N and 2×N layouts with 90° and 180° vertical mounting. The integrated range covers 100M, 1000M, 2.5G, 5G, 10G and HDBaseT, in LED and no-LED versions, with commercial (0–70 °C) and industrial (−40 to +85 °C) grades. Examples from the catalog include the Tab-Up Gigabit magjack SYT511Q218AC1A8D057 (±2% turns-ratio tolerance) and the Tab-Down 10/100 part SYT111B002HWA1D. Most of these panel-facing jacks are through-hole for mechanical robustness, and VOOHU supports customization when a specific footprint, mount or plating tier is required.
Most panel-facing RJ45 jacks — including integrated-magnetics (magjack) sink-type modules such as VOOHU's 1×1, 1×N and 2×N parts — are through-hole. The leads anchor through the PCB, which best resists the repeated plug-in force a connector sees. SMT RJ45 jacks exist for low-profile, space-constrained and high-volume designs and almost always add metal board locks for strength.
A through-hole jack's solder tails pass through plated holes and are soldered on the far side, so mating and cable loads are carried in shear by the hole barrel rather than only by a surface pad. SMT joints rely on pad adhesion plus added board locks. Because an RJ45 connector is rated for at least 750 mating cycles (IEC 60603-7), THT's mechanical anchoring is valued in front-panel, industrial and PoE designs.
Yes, if the part is specified for it. SMT RJ45 jacks use high-temperature thermoplastic bodies that withstand a J-STD-020 reflow peak of up to about 260 °C. Always confirm the moisture-sensitivity level (MSL) and reflow rating on the datasheet, and never reflow a part qualified only for wave or selective soldering.
The mounting method is mechanical; the contact system sets the electrical class. A Cat5e, Cat6 or Cat6A jack must still meet ANSI/TIA-568 NEXT and return-loss limits whether it is THT or SMT. What the mount influences is launch geometry and ground return, so for 2.5G/5G and 10GBASE-T keep tails short and give the shield a clean path.