Roadwolf 0 Posted May 22, 2019 Greetings! I am wondering how critical the wiring needs are for an RS485 2wire control connection? Does it need to be cat5 twisted pair all the way? or could it handle a short stretch of untwisted pair? I have a Pelco Spectra III I am working on controlling through RS485 from an imported DVR box, which has 2wire RS485 out, and supports pelco D and P protocols... Everything looks to be set up properly, however I am still getting no control. The only thing I wonder about, is that the control cable going out to the camera piggybacks onto 2 conductors which were additional unused wires in the 24VAC supply cable. I wonder if that would cause it to not function due to noise? Likely huh? That sucks because there is really no room in the conduit for another cable And since I am running this from NET300's I cant use coaxitron to control it. Share this post Link to post Share on other sites
jeromephone 6 Posted May 23, 2019 Does it work with a short length of cable to test. Share this post Link to post Share on other sites
cctvman1379 2 Posted May 25, 2019 From experience in the 2000,s when I worked in the cctv installation as a trainee I was always taught to use beldon screened 2 pair cable for data transmission and earth the screen wire I've never trusted cat5 or cat6 as a transmission line I have ptzs at home and have cabled in beldon cable and the job I'm working on at present I'm cabling the data in beldon it's just how I was trained and have carried it on for 15 years Share this post Link to post Share on other sites
philip7777 0 Posted May 30, 2019 Twisted pair is best to use for RS485 data control (CAT5 or CAT6) but I use a untwisted pair before and I was able to control a Pelco Spectra's. If you're still unable to control the PTZ do the following. Make sure RS485 polarity are correct. (RS485+ and RS485-) PTZ protocol and DVR are the same. (Pelco D ) PTZ and DVR Baud rate are the same ( 2400) Good Luck! Share this post Link to post Share on other sites
