Use a hub chip with the star wiring. You'll save yourself far more time than the cost of the hub.
njh On Wed, Jul 11, 2012 at 10:26:34PM -0400, Jeff Siddall wrote: > I realize this is more of a hardware rather than owfs question but it is > directly related to owfs functionality so here goes: > > I have a bunch of existing 4-wire untwisted telephone station cable I > want to use for 1-wire. It is all home run (star) wired currently which > is not ideal for a 1-wire bus. So my question is whether I would get > better performance with a star wired bus or if, by wiring pairs of wires > together at the "ends of the star" I would get better results making a > long serial connection. > > If that doesn't make sense below is some ascii art that will hopefully help: > > Star wiring method (where the lines represent the red/green pair of the > 4 wire telephone station cable and "+" represents a splice): > > |--10 ft--DS1825 > | > DS1490F--15 ft--+--20 ft--DS1825 > | > |--60 ft--DS1825 > > Serial wiring method using the same cable as above (where the lines to > the DS1825 represent the red/green pair of the 4 wire telephone station > cable and "+" represents a connection between a red/green and a > yellow/black pair): > > DS1490F--15 ft--10 ft--+-DS1825 > | > |--10 ft--| > + > |--20 ft--+-DS1825 > | > |--20 ft--| > + > |--60 ft----DS1825 > > The advantages to the star wiring example is that the distances between > each DS1825 and the DS1490 are shortest and only a single pair of wires > is required to each DS1825. The primary disadvantage seems to be signal > reflection at each of the three DS1825s. > > On the other hand the advantage of the serial wiring is that there is > only one end of the bus so only one signal reflection. However, the > maximum length from one end of the bus to the other has gone up to 120 > ft and for most of that there are bus signals traveling in opposite > directions along untwisted cable. > > Realizing that neither is ideal does anyone have a recommendation for > the best choice between the two? > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Owfs-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/owfs-developers ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
