RJ45 wiring protocol
Xima Domo cables use the T568B colour code with a custom, non-ethernet pinout. Never plug them into an ethernet switch — pins 1, 2 and 3 carry power.
Pinout
| Pin | Colour (T568B) | Function | RJ11 equiv. |
|---|---|---|---|
| 1 | white/orange | 3.3 V → | 1 |
| 2 | orange | 5 V → | 2 |
| 3 | white/green | GND → | 3 |
| 4 | blue | GND | — |
| 5 | white/blue | ← I/O 4 → | 4 |
| 6 | green | ← I/O 3 → | — |
| 7 | white/brown | ← I/O 2 → | — |
| 8 | brown | ← I/O 1 → | — |
Voltage and signalling
- Power rails: 3.3 V and 5 V on dedicated pins; two GND returns.
- I/O lines: 3.3 V CMOS logic, bidirectional (configured per port via the add-on).
- Current rating: limited by the NodeMCU-32S rails — keep total draw per cable conservative.
- Cable: any Cat-5e or Cat-6 patch cord. Length up to typical room runs (5–10 m) tested in practice.
Why custom
Sharing power and signal on the same cable means the relay modules don't need their own power supply: one patch cord covers everything. The trade-off is that the cable is incompatible with ethernet — clearly label both ends and the wall jack to avoid confusion later.
Full pinout details, current limits, and per-jack column assignment for the main board live in /docs/protocol/rj45-pinout.md.