Here’s a guidelines for reliable 1-Wire Network from Maxim:
The 1-Wire protocol was originally designed to facilitate communication with nearby devices on a short connection. 1-Wire was also a way to add auxiliary memory on a single microprocessor port pin. Methods were later developed to extend the 1-Wire protocol to network applications well beyond the size of a circuit board. This document discusses various aspects of 1-Wire networks and provides design guidelines for their reliable operation. Several appendices address fine-tuning the 1-Wire bus interface and illustrate 1-Wire communication waveforms in various conditions.
So what lengths are we talking about here? 10’s of cm? hundreds of meters?
Also, I would like to know how long is a piece of string?
Appearantly this goes upto several hundreds of meters. The examples go about branches that can be 150-300 meters, instead of the usual centimeters then you normally see on a PCB.