Windows NT Terminal Server Edition and all versions of Windows 2000 Server include Terminal Services. The principle of operation is that the server runs applications on behalf of network clients, which then only need to handle the transmission of key presses and mouse movements to the server, and the display of screen updates received from the server. Because the workstations have so little to do, their specifications can be basic and they are often called ‘thin clients’. By contrast, the network server will be subjected to considerable demands, so a system with very high processor and memory specifications is needed.

This arrangement is highly suited to common office duties such as word processing and email, where a full PC would be waiting for user input most of the time. Applications involving audio and video fare less well, with multimedia support limited to the generation of simple ‘beeps’. Enhanced audio support is available through optional Citrix services. For extra printing versatility, Windows 2000 Terminal Services can direct output back to a thin client’s locally-connected printer.

At first glance, it may seem that there are very few advantages to running Windows programs via Terminal Services rather than on local PCs. However, consider the fact that old systems can effectively be made to run modern Windows software, so giving them a whole new lease of life.

All kinds of management benefits result from Terminal Services, too: for example, new or updated software need only be installed once and it will immediately become available to all users. The possibilities for remote management are also dramatically increased, since terminal sessions can be established over dial-up and wide area links as well as local networks, and are almost as good as working at the server itself.

As standard, Windows Terminal Services accepts connections using Microsoft’s Remote Desktop Protocol (RDP), for which client software is available under Windows CE, and all desktop version of Windows later than 3.11. Adding Citrix MetaFrame enables connections from alternative platforms. Each client that will connect to a Terminal Server requires a Terminal Server Client Access Licence in addition to the normal Windows NT file/print CAL.