Deciphering Phone System Terminology

One of the more difficult aspects of choosing an office phone system can be trying to understand the terminology used to describe some the systems, their components, and features. Office phone systems are a part of the ‘tech’ field, so you should naturally expect that some of the jargon used would fall outside the scope of conversational English.

Here we have put together a small list of terms used by telephone systems dealers and vendors to help you familiarize yourself with the common ‘tech talk’ of the industry.

  • Ports – The term port refers to the number of connections that a certain phone system can handle, specifically when referring to PBX phone systems. The number of ports that a phone system has includes both the total number of incoming lines and extensions available.
  • Lines – Lines refer to the telephone lines coming into your business. Sometimes phone system vendors refer to lines as “trunks.”
  • Cabinet – Sometimes referred to as the “central office” or “CO,” “KSU” or “key system unit,” “central unit” and even “base.” A telephone system’s cabinet is the main box where internal routing, external routing, and configurations take place on PBX and key telephone systems.
  • Extensions – Extensions are essentially unique identifiers used within a telephone system’s internal network. Internal communication, fax machines, and modems can all operate without a dedicated phone line with the use of extensions.
  • Key Systems – Key Systems, also called key telephone systems, are the entry-level choice for small business phone systems. Each individual phone has a selection of buttons corresponding to the number of phone lines available. Key telephone systems offer support for up to forty employees, they are generally cheaper than PBX phone systems, and they offer features that suit many small businesses.
  • VOIP – VOIP, or Voice over Internet Protocol, is a type of internet phone system. Instead of using landlines, or regular telephone lines, to transmit conversations, VOIP phone systems rely on your business’ internet connection to send and receive telephone calls. VOIP phone systems oftentimes use traditional business telephones, but they require a router to translate your internet’s signal into a usable signal for standard telephones. VOIP is considered an alternative to key and KSU-less options for small office phone systems.
  • PBX – PBX phone systems, also known as Private Branch Exchange, are customizable phone systems for businesses with forty or more employees. The differences between PBX phone systems and key systems have become vague over the years, but generally, PBX systems offer more features, easier upgrades, and extensive customization opportunities, thus justifying a higher expense when compared to other systems.
  • KSU-less systems – KSU-less systems are for very small businesses where portability and price are more important than overall features and benefits. In contrast to other phone systems, there is no need for a “central office,” or cabinet, with KSU-less telephone systems because the telephones themselves have the necessary routing software installed. KSU-less telephone systems are usually only viable for companies with fewer than ten employees.
  • CTI – CTI, or computer telephony integration, is an optional set of applications that integrate your business’ telephone system with a computer. Features can include video conferencing, one-click dialing, incoming call routing, and a variety of other timesaving features that could be appealing to large businesses.
  • Hybrid – “Hybrid” phone systems are a mix between key systems and PBX telephone systems. While there used to be clear-cut distinctions between these two types of telephone systems, over the years these distinctions have become less apparent, thus leading to the use of the term “hybrid” for systems that offer the benefits and features of both types of these small business phone systems.