Ptz Operation & Compatible Dvr

[Newbie]

I'm just about to purchase a DVR ... and second hand one that originally came from Dynamic CCTV I believe. I have a requirment for a PTZ camera and have a question regarding DVR compatibility.

The more expensive DVR's support multiple protocols such as Pelco-D, Pelco-P. The DVR I am thinking of going for say's the following regarding PTZ Support "RS-485, Key Control (Pre-Assigned for each PTZ Command)".

I understand the RS-485 ... I have a computing / electronics background ... however what does the "Key Control (Pre-Assigned for each PTZ Command)" mean.

I assume it means different commands are issue to the PTZ when keys on the DVR are pressed ... but what about Protocols and Baud Rates ?

Do I need to be careful about which PTZ I go for ?

Anyone any experience using Dynamic DVR's (god & bad) and any PTZ use ?

Many thanks.

[topalarms]

Dynamic sell reasonable kit, the current dvrs should have proocols for Pelco P & D, Fastrax and Panasonic and most PTZs can comply with Pelco - ask Dynamic for specific details for your model dvr.