Hi,
My church recently purchased a Hsility PTZ controller and a PTZ camera.
My problem is that the PTZ camera is connected via USB and doesn't have an IP address.
I was told by the camera seller through Amazon that the the problem would be solved by connecting them via RS485.
The controller does not have a RS485 port, but does have a RS422 receptacle.
What would I have to buy in order to connect these two pieces of equipment?
Suggestions?
Thanks,
JP

 

The RS-485 and RS-422 standards are electrically similar, and it may even be possible to directly connect the RS-422 and RS-485 devices together for communications (otherwise you could use a RS-485 to RS-422 converter; here is one example https://www.commfront.com/products/...ter-extender-converter?variant=39593903489121) . However, this is only one small part of the problem. There must also be a digital communications protocol that runs on top of the RS-485/422 connection that both devices support.

As an analogy, think of RS-485 and RS-422 as telephones, one a land line and another a cell phone. Both allow two people to talk to each other, and each of them could even be using a different type of telephone. The protocol in this analogy is the language that each person speaks. If both people speak English, then they can successfully have a conversation. However, if one person speaks only English and the other speaks only French, they will not be able to communicate with one another.

Therefore, you first need to find out what communication protocol(s), if any, are supported by both the controller and the camera.

 

Thank you, Jshulze. That helps. I'll work on that and hopefully gain control of them. Have a great evening!

 

There is eternal confusion on the part of some suppliers with regard to RS-422 and RS-485. Some assume that anything with 2 wires is RS-485 and with 4 wires RS-422. This is plain wrong. So I'd advise to connect it, just see if it works.

 

There is such a thing as 4-wire RS-485 that uses four signal lines. And, as NetworkMan already stated, some manufacturers/suppliers that claim a device is RS-422 is really a 4-wire RS-485 device.

Because RS-485's electrical specifications are within the range of RS-422's specifications, RS-485 meets the requirements of RS-422. For this reason, it is rare to find a modern transceiver that is RS-422 only. Most transceivers support both RS-485 and RS-422, since if you support RS-485, you're also compliant with RS-422.

A 4-wire RS-485 device can be directly connected to an RS-422 device and communications will work. In order to connect a 2-wire RS-485 device to an RS-422 device (or a 4-wire RS-485 device), you must jumper the RS-422 (or 4-wire RS-485) device's transmit and receive terminals (typically, you would jumper A to Y and jumper B to Z). However, whether communications will work or not depends on whether the RS-422 device (or 4-wire RS-485 device) constantly drives the bus (since in RS-422 there is only one device that can drive the bus, so some devices simply always drive the bus). If this is the case, then communications will not work between a 2-wire RS-485 device and an RS-422 (or 4-wire RS-485) device and a dedicated RS-422 to RS-485 converter must be used inline between the two devices.