The 4 types of phones systems business would use:
This one is the least expensive. It is a basic phone system for very small companies that have fewer than 10 employees. It has basic features and features. This system does not allow room for expansion and can only support 2 to 4 lines but it is mobile and you can take the system with you when you transfer to a different office. You would need to do the installation, programming and maintenance.
Key Systems or KSU
This system most traditional type of phone system you can purchase and is for business with 5-40 employees. It is similar to the Key-less system with all the basic features, however more advanced feature can be added and it can be upgraded as your company expands. It offers multiple lines and is supported by a key system unit (KSU). The other difference is this system requires a central key system unit or a KSU to support the phones.
PBX or Private Branch Exchange System
This is the most common business phone system but can be quite pricy. It is generally for a company with 50 or more employees. The PBX system has both basic and advanced features. A central PBX cabinet is required to power it. It is flexible, has many features and will meet the requirements for a larger and busy workplace. The PBX easily integrates with other technologies and you can expand this system to carry more advanced features. This system requires installation from a telecom vendor and is one of the most expensive systems but has the most advanced options and more secure.
Voice over Internet Protocol or VoIP System
The VoIP system can work for small or large business is for any sized company and works well. This works through the internet and this system sends calls through the Internet as opposed to through traditional phone lines, so anyone using the system can be anywhere in the world while using the same phone number making it portable.
It is the newest technology and quickly becoming popular amongst companies and consumers. Great for companies that are Global as for a minimal fee, you can communicate with other offices around the world. VoIP still requires you to have a phone service that can connect you to other offices using traditional systems and best used in conjunction with your existing system. This system is very mobile and can be connected to your customers and suppliers without changing numbers.