The four main types of business telephone systems (key telephone systems, private branch exchange telephone systems (PBX), KSU-less telephone systems and voice over internet protocol) all provide the same basic function (i.e. to make and receive telephone calls), but there are significant differences between them. If you need a telephone system for your business, then it is worthwhile learning about each of the systems available to ensure that you get the one that is best suited to your particular circumstances.... Read more