Standard CCTV and HD CCTV systems are based around a central recorder (centralised systems). The recorder will have a fixed number of inputs, typically 4, 8, 9, 16 or 32. You can use any number of cameras up to the maximum inputs on your recorder with each system.
If you require more cameras than your recorder can handle you will need to add an additional recorder. These can be controlled and viewed from a single location using a CMS (central monitoring station) software package which will often allow up to 64 cameras to be monitored.
To achieve this the recorders will need to be connected to a network. A client or computer on the network will host the CMS software and connect to each recorder.
A Keyboard controller will allow the operator to switch between the recorders and controll PTZ cameras etc attached to each.
Example CCTV system plan with linked recorders