Security and IoT Gateways: Stacking Radio and Ethernet Modules on Headers

Radios must be swappable

Cameras, NVRs, door stations and energy gateways certify a specific 4G or Wi-Fi module. Changing carrier or silicon should mean a new daughter, not a new main board. Public gateway schemes use 0.80–2.00mm dual-row headers for power, UART/USB, reset, GPIOs and sometimes RMII. That is the modular pin/female job: 2×20 is common, and the antenna still needs air to the lid.

Pinout

• Power and ground on the sides or symmetric; derate for 4G bursts, not average current.
• Group reset, boot and flight-mode for test pads; keep them off the SMPS return.
• Keep USB/RMII on the module if you can; if they must cross the header, stitch grounds.
• Add antenna and SIM height into the stack — the header is not the only keep-out.

Mechanics

A 1U NVR front panel is a box-header/ribbon problem; a module sitting on the MCU is a straight pin/female stack. Outdoor cameras see condensation: gold, wash, adhesive if the port will never be serviced. Indoor one-time SMT is fine; a moving PTZ prefers THT or screws.

Not a MiniPCIe stand-in

Gold-finger MiniPCIe/M.2 stays gold-finger. Headers fit stamp-hole modules and house-made GPIO cards. MIPI camera boards need dedicated BTB.

Junjia can match 2.00/1.27mm SMT or THT sets to a gateway pin count. Put burst current, antenna height and field-swap on the RFQ so the lid does not crush the RF connector.