DeMoD One Hybrid Instrument Cable – Manufacturing Specification

License: CERN Open Hardware Licence Version 2 – Strongly Reciprocal (CERN-OHL-S v2)
Source Location: https://github.com/ALH477/DeMoD-One-Cable
All derivatives and products manufactured from this design must also be licensed under CERN-OHL-S v2 or later.

1. Overview

Single-cable solution providing simultaneously:

• Analog instrument/line-level audio (mono or stereo) via ¼″ TRS
• Passive 48 V PoE (IEEE 802.3af/at Mode B compatible)
• Full-duplex 1000BASE-T Ethernet (HydraMesh + StreamDB traffic)

2. Electrical Specification

Parameter	Requirement
Audio channels	Mono (Tip+Sleeve) or Stereo (Tip+Ring+Sleeve)
Audio impedance	≤ 100 Ω balanced
Audio max level	+24 dBu (line) / +12 dBu (instrument)
PoE delivery	30 W continuous (Mode B, pins 4-5 +, 7-8 –)
Ethernet	1000BASE-T, full duplex
Shielding effectiveness	≥ 85 dB @ 1 MHz – 1 GHz
Crosstalk (audio ↔ Ethernet)	≤ –90 dB @ 20 kHz

3. Cable Construction

• Overall diameter: 8.5 ± 0.5 mm
• Jacket: Matte black PVC with orange tracer stripe (Pantone 165 C)
• Conductors:
  – 2 × 24 AWG stranded OFC (audio, individually foil-shielded, twisted)
  – 4 × 26 AWG solid OFC pairs (Cat6, 100 Ω impedance)
• Shielding: Al-Mylar foil + tinned copper braid ≥ 85 % coverage
• Fillers: Cotton or PE for roundness
• Temperature rating: –20 °C to +80 °C

4. Pinout (DeMoD One Standard – T568B)

RJ45 Pin	Color	Function	¼″ TRS
1	Orange/White	TX+	—
2	Orange	TX–	—
3	Green/White	RX+	—
4	Blue	Audio Tip / PoE + (bridged)	Tip
5	Blue/White	Audio Ring / PoE + (bridged)	Ring
6	Green	RX–	—
7	Brown	PoE – (bridged)	—
8	Brown/White	PoE – (bridged)	—
Shell	—	Overall shield / Sleeve	Sleeve

5. Connectors

• Instrument end: Neutrik NP2X-BAG-D silentPLUG (black shell, gold contacts, laser-etched “DeMoD One”)
• Device end: Hirose TM21P-88P or equivalent shielded RJ45 with metal shell bonded to overall shield
• Strain relief: Integrated overmolded boots, ≥ 50 N pull strength

5.1 Recommended Mating Connectors

For optimal compatibility, noise rejection, and spec compliance in device integration (e.g., HydraMesh hubs or StreamDB nodes), the following female receptacles are recommended. These ensure shielding continuity (≥85 dB), PoE passthrough (up to 30W), and balanced audio handling (≤100Ω impedance, +24 dBu max).

• Instrument End (Female ¼″ TRS Jack):

  • Primary Recommendation: Neutrik NJ3FP6C-BAG
    • Gold-plated contacts for low-noise performance; D-size chassis mount with integrated strain relief for flush panel installs. Matches cable's black/gold aesthetic and supports mono/stereo switching.
    • Cost: ~$5-7 USD (bulk).
  • Alternatives: Switchcraft 112BX (budget brass option, ~$2 USD); Amphenol CTJ (IP67-rated for rugged/outdoor use, ~$10 USD).
  • Integration Note: Tie ground lug to overall shield for enhanced crosstalk isolation (≤–90 dB @ 20 kHz).

• Device End (Female RJ45 Jack):

  • Primary Recommendation: Hirose TM21R-88P(01)
    • Direct mating for TM21P-88P plug; shielded (STP) with metal yoke for shield bonding; supports Cat6/100Ω impedance and PoE+ (IEEE 802.3af/at) without thermal issues. Optional LEDs for link/activity.
    • Cost: ~$1.50-3 USD (bulk).
  • Alternatives: Amphenol RJHSE-5380 (PCB-mount with auto-MDIX, ~$2 USD); TE Connectivity 615004147621 (toolless keystone for AV panels, ~$2 USD); Belden 1A-09500 (high-density option, ~$4 USD).
  • Integration Note: Ensure IDC terminals rated for 48V/1A; certify for HiPot (1000V DC) and Ethernet eye diagram integrity at 1 Gbps.

These recommendations are non-mandatory but align with CERN-OHL-S v2 reciprocity—source from Digi-Key/Mouser for open BOMs. For custom breakouts (e.g., TRS-to-RJ45 panels), combine both in a shielded enclosure.

6. Standard Lengths & Retail Pricing (1k-unit MOQ)

Length	BOM cost (approx.)	Retail price	Margin
0.5 m	$8.40	$39	~78 %
1 m	$9.80	$39	~75 %
3 m	$12.50	$49	~74 %
6 m	$17.00	$69	~75 %
10 m	$23.00	$89	~74 %

7. Testing Requirements (100 % production test)

• Continuity & correct pinout
• HiPot 1000 V DC (1 min) audio vs. Ethernet
• PoE load test 30 W
• Ethernet eye diagram & packet test (1 Gbps)
• Shield continuity

8. Packaging & Branding

• Recycled card sleeve
• QR code → GitHub Source Location + quick-start guide
• Sticker: “Power + Audio + Mesh”

This specification is complete and ready for immediate quotation and production by any competent cable manufacturer (JLCPCB Cable, Moonlight Cables, Canare, Belden OEM, etc.).

DeMoD LLC – December 2025
CERN-OHL-S v2 – Strongly Reciprocal