1-wire

rough draft

The 1-wire network is a communications bus system designed by someone(?) at Dallas Semiconductor (now part of Maxim Integrated) that provides low-speed data, signaling, and power, using up a total of one pin on the CPU no matter how many peripheral chips are on that bus. (Other ways of connecting a peripheral to the CPU either require another pin for each peripheral, or require more pins for the first peripheral, or both).

The 1-wire network is perhaps the most popular way to measure temperatures at many different locations and send that data back to one central processor.

[[Media: A Guide to the 1WRJ45 Standard.pdf]]

It makes it easier to troubleshoot if each PCB has 2 RJ45 connectors (or a dual RJ45 connector), with 1 LED indicating power and 1 LED indicating 1-wire signals.

For clarity each of the 8 wires from the standard 1WRJ45 connector may be labeled with the following 2-letter PCB silkscreen abbreviation:

1 5R (VCC return) 2 +5 (VCC power) 3 AR (Analog return) (?) 4 OW (one-wire I/O) 5 OR (one-wire return) 6 AS (Analog signal) (?) 7 +V (V raw power) 8 VR (V raw return)