RS-485 to RS-422 converter

[sfjensen 0]

Has anyone had success using a RS-485 to RS-422 converter to communicate from a video server that supports RS-485 to a PTZ camera with RS-422 protocol ?

 

I have a Pelco Esprit ES31C22-2W which communicates with RS-422 for PTZ and camera control, my Geovision NVR supports RS-485. The camera is about 1400 ft from the NVR, and about 600 ft from a network connection. I am considering a Geovision video server and a RS-422 to RS-485 converter. Has anyone had success with this setup? Any suggestions for an solution would be appreciated

[survtech 0]

There are very few differences between the two. Most RS-485 devices will work on RS-422 systems and vice versa. The big difference is the number of devices that can be daisy chained (10 for RS-422 vs. 32 for RS-485) and whether a single pair can handle two way (bidirectional) communications or just unidirectional. Since PTZ control is usually only unidirectional, the two communications systems are virtually interchangeable.

 

Don't confuse the serial communication standard with the protocol. Protocols are not interchangeable.

 

Link to FAQ

[sfjensen 0]

There are very few differences between the two. Most RS-485 devices will work on RS-422 systems and vice versa. The big difference is the number of devices that can be daisy chained (10 for RS-422 vs. 32 for RS-485) and whether a single pair can handle two way (bidirectional) communications or just unidirectional. Since PTZ control is usually only unidirectional, the two communications systems are virtually interchangeable.

 

Thanks for the reply survtech.

 

Do you think I can just use the two wire system to comunicate from the video server to the pelco ptz?

[survtech 0]

It wouldn't hurt anything to try. We commonly interchange the two with no problems.

[Soundy 1]

^Seconded - it SHOULD work just fine, and it won't hurt anything to try it first. If it works, great; if not, then you can look at adding a converter.

[sfjensen 0]

The camera is due in this week, I will let you know how it works out. Thanks for the help.

[Okinawamike 0]

I have 20+ of the Pelco Esprit ES31C22-2W connected to a wireless system and run all over two wires for P/T/Z

 

Don't fall for the Pelco sales pitch that they must be connected to the CM6700 or a CM9760-CDU-T.

 

I have made this work straight from the DVR P/T/Z outputs.

 

Also, ran this to the Video Servers, Pelconet 350 and most work fine. A few lock up's now and then.

[CCTVguru1 0]

www.alfatron.com.au

 

I hav used plenty and they work realy well. They have a tri-state output controlled by the RS232 RTS pin