volatileacid 0 Posted January 22, 2009 Hello there. I take it, PTZ functionality cannot be enabled without additional wiring between a camera and a DVR? To enable PTZ, does one need to enable communication via twisted pair (?)between the camera and DVR (or other device) to the RS485 port? What if there is more than one cam - is an intermediary device then required? Cheers - and sorry if this is a stupid question. Share this post Link to post Share on other sites
survtech 0 Posted January 22, 2009 Hello there. I take it, PTZ functionality cannot be enabled without additional wiring between a camera and a DVR? True, unless the camera and DVR support "up-the-coax" control. That is both rare and not the most reliable method. To enable PTZ, does one need to enable communication via twisted pair (?)between the camera and DVR (or other device) to the RS485 port? Usually. The vast majority of PTZ's use RS422/RS485 communication for data. Although RS422/RS485 can be bi-directional, for PTZ control you only need 1-way communication - transmit at the controller and receive at the PTZ. CAT-5 twisted pair is the most common method, using one pair, but I've also used 22/2 shielded and even 18/2 twisted power cables for short runs. Using CAT-5, control can be run up to 4000 feet. What if there is more than one cam - is an intermediary device then required? It depends. You can safely daisy-chain up to three PTZ's on one data line; even more if you turn off the termination on all but the last one in the chain. If you can't daisy-chain due to the PTZ's being in widely spaced locations, you can use a "code distribution unit". Pelco makes the CM9760-CDU-T which handles up to 16 PTZ's (more if you daisy-chain on each output). The less expensive alternative is the Kalatel KTD-83, which has 5 outputs, and it's brother, the KTD-83-16, that has 16 outputs. Share this post Link to post Share on other sites
volatileacid 0 Posted January 22, 2009 Wow, superb response. Thankyou kindly - makes a lot more sense now Share this post Link to post Share on other sites
Soundy 1 Posted January 23, 2009 Hello there. I take it, PTZ functionality cannot be enabled without additional wiring between a camera and a DVR? True, unless the camera and DVR support "up-the-coax" control. That is both rare and not the most reliable method. Also known as "Coaxitron", if you're looking around for it. To enable PTZ, does one need to enable communication via twisted pair (?)between the camera and DVR (or other device) to the RS485 port? Usually. The vast majority of PTZ's use RS422/RS485 communication for data. Although RS422/RS485 can be bi-directional, for PTZ control you only need 1-way communication - transmit at the controller and receive at the PTZ. CAT-5 twisted pair is the most common method, using one pair, but I've also used 22/2 shielded and even 18/2 twisted power cables for short runs. Using CAT-5, control can be run up to 4000 feet. I've done it with a variety of wiring as well. In some cases, I've even successfully run control, video and power over a single piece of Cat-5e: one pair for serial, one for video (with baluns) and two for power. What if there is more than one cam - is an intermediary device then required? It depends. You can safely daisy-chain up to three PTZ's on one data line; even more if you turn off the termination on all but the last one in the chain. If you can't daisy-chain due to the PTZ's being in widely spaced locations, you can use a "code distribution unit". Pelco makes the CM9760-CDU-T which handles up to 16 PTZ's (more if you daisy-chain on each output). The less expensive alternative is the Kalatel KTD-83, which has 5 outputs, and it's brother, the KTD-83-16, that has 16 outputs. This may depend on the cameras and/or controller used, too... I have three Capture PTZs connected "star"-style to a Capture controller, with no problems. Either way, you're really just connecting all the cameras in parallel. Share this post Link to post Share on other sites
