Aside from making sure walk in customers are greeted with courtesy, the No. 1 way most people gain an impression about a business is through telephone conversations. If a telephone system at a business doesn't do its job, the people who make the company tick will never have a chance to do theirs.
There are a number of different telephone systems available for companies of all sizes. From large services that involve separate direct lines for each desk in an office building to more simplistic set ups, the variety runs the gamut. The most important things about any system, however, remain reliability, ability to handle incoming calls, and the quickest and best method for getting people on the other end of the line in contact with actual humans within the company they're calling.