What this connector is
The Amphenol 79821-156HLF is a 56-position dual-row BERGSTIK II male header, board-to-board style, terminated via through-hole solder. The 0.100" (2.54 mm) pitch and 0.100" row spacing give it the standard dual-row footprint familiar from JEDEC and industrial I/O board stacks — the kind of header that fills a multi-function card's edge bus or ties two parallel daughterboards in a backplane-less mezzanine. It is unshrouded and push-pull fastening — no tool-assisted latch, just a friction-seated mate. That makes it right for applications where the board stack is set at assembly and not field-serviced. Square male pins in phosphor bronze offer mechanical column strength through the hole; the 0.200" (5.08 mm) post length leaves enough land for a wave-solder barrel without exceeding typical PCB thickness budgets. All 56 positions are loaded — every circuit slot carries a pin. Contact finish is gold or Amphenol's Gold GXT (a gold-flash variant) at 30.0µin (0.76µm) on the mating side. At this thickness the plating supports repeated mating cycles better than tin, making it the right choice when the assembly gets a production test mate or field service rework.
Key ratings
Current is rated 5 A per contact at 110 V. The insulation height of 0.100" (2.54 mm) matches the pitch, so the housing standoff over the board surface is consistent. The black housing is rated UL94 V-0.
How it fits the BOM
The 56-position count is the primary BOM gate — confirm the target board design calls for exactly 56 pins across this connector's footprint. The pitch and row spacing (both 0.100" (2.54 mm)) are standard; any dual-row 2.54 mm receptacle with matching circuit count mates mechanically. The push-pull, unshrouded style means keying relies on the housing or board keep-out, not the header itself — specify a keyed receptacle if mis-mate prevention is required. Plating is gold or Gold GXT at 30.0µin (0.76µm). Gold GXT is a controlled wear-surface alloy used where cycle life matters.