Class 4 vs Class 5 PBX Differences

Usually, you will find that when talking about PBXes, they are classified in Class 4 and Class 5. So, obviously, your next question is: What is the difference between a Class 4 and a Class 5 PBX?  I will try to explain as clear as possible.

Class 5

A Class 5 PBX deals with end-user. It provides final-user services such as Voice-Mails, Conference rooms, IVR and many another kind of services that a phone user may need. This kind of switches deals with the user interaction (SIP endpoints such as Soft/Hard phones). So, in general terms, you can state that principal client of a Class 5 PBX is end-user.

It is very common to find them in the retail market.

Class 4

Class 4 PBX is a little different. They don't deal with end-user, but instead, they deal with other switches. If you are familiar with networking, you can see Class 4 switch as a router that is connected to other routers. Class 4 ones do not offer conference rooms, IVR or any other endpoint item; authentication is usually tied to IP rather than registration.

You can find this kind of switches on the wholesale market.