Pin Header Jumpers: Shorting Caps on 2.54mm Configuration Pins

The smallest switch on the board

A jumper (shorting cap) is a housing with a metal bar that shorts two adjacent pins. Dev boards use it for boot mode and pull-ups; industrial boards use it for backup paths or RS-485 termination. It mates to a pin header, not a female or box header.

Match these

• Pitch: a 2.54mm cap will split or bend a 2.00mm header.
• Pin size: typically 0.64mm square; thin pins go slack, thick pins swell the cap.
• Plating: gold for frequent moves; tin if it is factory-set and never pulled.
• Height: leave finger room beside tall capacitors.

Use

Short only the intended pair — do not skip a pin on a diagonal. Pull straight up. If customers keep setting it wrong, silkscreen ON/OFF or replace the jumper with 0Ω / a DIP switch in production and leave jumpers on the debug strip only.

Junjia can supply headers and shorting caps at the same pitch. State cycle count when the jumper must be field-changeable.