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

Plugboard Assembly - Mechanical Design Specification

Status: Draft Project: Enigma-NG Author: Izzyonstage & GitHub Copilot Version: v.0.1.0 Associated Hardware Revision: Rev A Last Updated: 2026-05-08

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: 64ร— 6.35 mm (1/4") mono switched jack sockets (Tip + Switch contact tied to decode-board spade terminal; Sleeve to paired encode-board spade terminal). 128 jack sockets total across both passes. Assembly BOM โ€” see ยง7. No PCB RefDes assigned; parts are panel-mounted and wired via harness only.

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 there are 64 panel-mount 6.35 mm (1/4") mono switched jack sockets, each wired between the two Encoder Modules assigned to that pass (one decode role, one encode role). The mapping is strictly 1:1: jack socket N connects line N on both boards simultaneously โ€” every jack therefore has at least one pin terminated on each of the two ENC boards.

  • Decode side (Tip + Switch): both contacts of jack socket N wire to spade terminal N on the decode Encoder Module (J2-J65, where J(N+1) = line N).
  • Encode side (Sleeve): the Sleeve contact of jack socket N wires to spade terminal N on the encode Encoder Module (J2-J65, same index).

Per pass: 64ร— 3-wire assemblies (Tip + Switch + Sleeve), each terminated with 6.35 mm female crimp spade terminals.

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

7. Assembly BOM

These parts are panel-mounted and connected to the PCB via wiring harness only. They carry no PCB RefDes and do not appear in any board-level BOM.

Item Description MPN Manufacturer Source Qty per Pass System Qty
Jack socket 6.35 mm (1/4") mono switched jack socket, panel-mount (no standard MPN) generic eBay โ€” SaiBuy.Ltd 64 128

8. Cross-References

Document Description
design/Electronics/Encoder/Design_Spec.md Generic Encoder Module spade-terminal pinout (J2-J65), CPLD role allocation, jack-sensing electrical spec