All programming is done locally for each door via a keypad provided with the controller. There is no need for computers of any kind. Ideally suited for small numbers of doors and users. Compact access controllers have the reader (usually a keyboard) and controller built into the same unit. These systems offer the lowest cost.
With an online networked solution, you can control an unlimited number of doors and sites from a single server.
The software allows simple programming and monitoring of the system. If the connection is lost or the PC switched off the controllers carry on as normal.