RS-485 amplifier

[koolmer 0]

Does that exist? I have several PTZ with a lot of distance in between (Warehouse) and the last camera cannot be controlled properly. Sometimes it works - sometimes not. I assume that the distance is just too big. The protocol that I use is Vista 485 (www.vista-cctv.com).

 

koolmer

[survtech 0]

RS422/RS485 is supposedly good for distances up to 4,000 feet using proper cable (twisted pair or shielded twisted pair). Are you daisy-chaining them? If so, make certain you turn off the termination on every unit except the last one in the chain.

 

 

 

GE Security Kalatel KTD-83 RS422 Data Signal Distributor

(http://www.gesecurity.com/portal/site/GESecurity/menuitem.f76d98ccce4cabed5efa421766030730?selectedID=530&seriesyn=true)

 

Pelco CM9760-CDU-T Code Distribution Unit

(http://www.pelco.com/global/en/products/analog-systems-controls/range-presentation.page?p_function_id=10502&p_family_id=10276&p_range_id=5536)

[koolmer 0]

Thanks for your reply. Yes, I am daisy-chaining them and the distance is approx. 900 meters in total. Termination is switched off on all cameras except for the last one of course. Will these amplifiers work with any RS-485 or are they limited to the protocol of the manufacturer?

[survtech 0]

Thanks for your reply. Yes, I am daisy-chaining them and the distance is approx. 900 meters in total. Termination is switched off on all cameras except for the last one of course. Will these amplifiers work with any RS-485 or are they limited to the protocol of the manufacturer?

They'll work with any RS422/485 signals. Technically, they're not amplifiers but signal distribution devices but they will allow longer runs if placed midway. The cheapest device would be the KTD-83.

[hardwired 0]

Thanks for your reply. Yes, I am daisy-chaining them and the distance is approx. 900 meters in total. Termination is switched off on all cameras except for the last one of course. Will these amplifiers work with any RS-485 or are they limited to the protocol of the manufacturer?

They'll work with any RS422/485 signals. Technically, they're not amplifiers but signal distribution devices but they will allow longer runs if placed midway. The cheapest device would be the KTD-83.

 

Those devices are for RS422, but I'm not sure that they will work for RS485 correctly, the Pelco product, at least, is only listed as RS422 unidirectional, where RS485 is a bidirectional protocol.

 

I'd take a look at the repeater from B&B model #485OP ,http://www.bb-elec.com/product_family.asp?familyid=1, that seems to be perfectly suited for what he needs.

[survtech 0]

Nonsense. RS422 and RS485 are, for all practical purposes, identical from a CCTV standpoint unless you need bidirectional communication. Since PTZ control is unidirectional, there is no difference. Both RS422 and RS485 are balanced data transmission with 100 ohm termination.

 

We use both the CDU-T's and the KTD-83's throughout our systems to distribute PTZ control to around 200 Pelco Spectra II, III and IV's from a Pelco 9780 matrix and they work just fine. We have CDU-T units in our control room and the KTD-83's co-mounted in the field with power supplies and "66" punchdown blocks. They both work flawlessly.

[koolmer 0]

I will get one of those. Thank you!

[marvincctv 0]

This Marvin Young

 

RS485 signal amplifier do exist. When the RS485 communication signal be affected by 220V or other signal or the transmission distance is too much long, you will need amplifier .