All scanners are controlled by the computer to which they are attached and the user can adjust scan settings via control software. It means that SOHO scanners don’t necessarily have their own control units, although some manufacturers help the beginner and insert a few “fast scan” buttons (generally, in the front panel of the case).
Fast scan buttons are something you can well do without
Each button is marked by an icon. Typical functions assigned to the buttons include: launching a standard scan operation with output to the printer, to your e-mail client, to the fax and so on. Of course, there are definite scan settings for each button. Anyway, when you push a button, an application responsible for it will start up. By the way, control units are available in few SOHO scanners, and are always missing in professional machines.
Some manufacturers often remove certain options from the scanner driver, which most of the users don’t use. For example, SOHO scanners from Hewlett-Packard don’t allow changing the gamma, loading ICC profiles and so on. However, Hewlett-Packard is known for pleasing its customers with “fast scan” buttons in most products.