Mechanical Plugboard Assembly Design Spec - thepinkmile/Enigma-NG GitHub Wiki

Plugboard Assembly โ€” Mechanical Design Specification

Status: Draft Project: Enigma-NG Author: Izzyonstage & GitHub Copilot Version: v0.2.0 (migrated from Plugboard/Design_Spec.md) Associated Hardware Revision: Rev A Last Updated: 2026-04-20

1. Overview

The Plugboard Assembly contains two independent plugboard passes. Each pass uses:

  1. one Encoder Module in a decode role,
  2. one 64-jack passive patch field, and
  3. one Encoder Module in an encode role.

The full Plugboard Assembly therefore contains four Encoder Modules total:

  • PLG_PASS1_DEC
  • PLG_PASS1_ENC
  • PLG_PASS2_DEC
  • PLG_PASS2_ENC

Each jack socket bridges one decode-board output line to one encode-board input line within the same pass. With no patch cable inserted, the jack's normally-closed contact preserves identity mapping.

2. Functional Requirements

ID Functional Requirement Notes Satisfied By / Cross-Ref
FR-PLG-01 Accept encoder input signal via the passive plugboard jack interface Per pass: 6.35 mm (1/4") mono switched jack (Tip + Switch contact on decode board; Sleeve on encode board) See design/Electronics/Encoder/Design_Spec.md for generic Encoder Module interconnect details

3. Design Requirements

ID Design Requirement Specification Satisfied By / Cross-Ref
DR-PLG-01 Plugboard plug interface Per pass: J1 = 6.35 mm (1/4") mono switched jack (Tip + Switch contact tied to decode-board line; Sleeve to paired encode-board line) BOM J1 (x64 jack sockets per pass, 2 passes total)

4. Plugboard Jack-Sensing

For signal polarity, insertion-detect logic, RC debounce circuit, and detection latency, see design/Electronics/Encoder/Design_Spec.md ยง7 Plugboard Jack-Sensing.

5. Physical Harness

Per plugboard pass:

  • 64x 3-wire assemblies (Tip wire + Switch wire + Sleeve wire), each terminated with 6.35 mm female crimp spade terminals.
  • Tip and Switch both terminate on the paired decode Encoder Module output bank.
  • Sleeve terminates on the paired encode Encoder Module input bank.

The full Plugboard Assembly duplicates this harness set for Pass 1 and Pass 2.

6. Cross-References

Document Description
design/Electronics/Encoder/Design_Spec.md Generic Encoder Module spade-terminal pinout, CPLD role allocation, jack-sensing electrical spec