If I recall....a vendor told me the other day, 350mA is what you can push thru a CAT5 cable pair. Never did verify it tho... >From: Jesse Lackey >Reply-To: pic microcontroller discussion list >To: PICLIST@MITVMA.MIT.EDU >Subject: [EE]: using cat-5 ethernet for power & rs-485 >Date: Fri, 10 May 2002 03:18:39 -0400 > >Hello all, > >I'm researching how to control possibly 640 strobe or LED bundle lights >via computer. These will go on the outside of a building. > >Leaving the circuitry aside for now (PIC + whatnot), in order to keep >wiring sane I'd like to use just one cable of a commonly used type >(cheaper). > >The current idea is to daisy-chain 16 together (spaced at 4' intervals) >with ethernet, using 2 pairs for transmit/receive rs-485, and the other >2 pairs for power (say 12v) and ground. Cat-5 is available in >ruggedized outdoor, exposed-to-the-sun versions. > >The AWG specified for the cables I'm looking at is 24 (pure copper). >There is no mention of how much power can go thru each wire, or pair, or >thru the RJ-45 connector for that matter. 28.6Ohms DC resistance for >1000ft is specified. > >So each module will have an RJ-45 "in", and an RJ-45 "out", and 4' of >cable between. The run from the first one to the rs-485 + power supply >inside will be longer of course (maybe 25'). > >I couldn't find a current-capacity for given AWG table anywhere. Help? >Also, does this seem like a reasonable plan in general? The data rate >required isn't high - 56Kbps should be sufficient. > >Thanks for any tips! >Jesse > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics