KSU-less systems are the cheapest phone systems and offer limited features. They are usually suitable for small businesses with less than ten employees. KSU-less system does not need a cabinet as the telephones have all the routing software installed in them. A KSU-system has certain best planar magnetic headphones. These systems are not compatible with Key and PBX systems and may offer little utility if your business expands and upgrades to a better phone system. Additionally, these systems are not supported by vendors and you will have to take care of their servicing and installation.
Key Systems or Key Telephone Systems are suitable for medium-scale businesses with less than forty employees. A set of buttons corresponding to the number of available phone lines are provided with each phone. These phone systems can be easily upgraded but they offer little customization abilities in comparison to other systems.
Private Branch Exchange (PBX) phone systems offer a wide range of features, and can be easily upgraded and customized. Though most expensive, they enable cost reduction as you scale, making them most suitable for large businesses with over 100 employees.
Hybrid systems- These systems combine the cost-effectiveness of key systems with the range of features of PBX systems.
Voice over Internet Protocol (VoIP) is a phone system that uses the internet for call routing and forwarding. It provides a cost-effective and portable substitute for KS and KSU-less systems. The router can be taken from place to place and plugged into any internet connection. However, each time the geographic location of the router is changed, you must inform your VoIP service provider, so that emergency calls can be routed to the nearest call centre. The biggest disadvantage of VoIP systems is their complete dependence on the internet connection. A poor connection deteriorates call quality, whereas connection loss can cause the system to fail altogether. Remember to discuss security and encryption issues with your provider before purchasing a VoIP phone system.