The easiest way to get a basic understanding of an extension is to call it a telephone. That is, if you work in an office, and you have a phone on your desk, that would be an extension! In your workplace, your boss and coworkers might have extensions too. Depending on the kind of phone system you have, you can dial them directly by picking up your phone and dialing their extension number. Then their phone rings, and boom, you're talking. Isn't the future great?

The important thing to understand with VOIP systems like NWVOX, is that extensions and phone numbers do not necessarily need to be matched 1 to 1. This means that unlike your home phone or cell phone, you aren't limited to one telephone number and one physical telephone associated with it. You can have any number of telephone numbers, and any number of extensions!

You can have 10 extensions, but only one telephone number.

You can have 10 extensions, and 10 telephone numbers.

You can have 1 extension and 10 telephone numbers.

The secret to this is something called "call flow", which is discussed in detail in another article. The basic idea is that depending on the needs of your business, we can make any of your phone numbers ring any number of your extensions. When a customer calls, only the extensions you want to ring will get the call. This way, you can direct your callers to the right people, fast. 

So, what about users with an extension, but no phone number? That's easy. You can still route calls to them in your call flow, even though they do not have a direct line. Since they have an extension with a 4-digit number, anybody in your organization can dial them directly, too. And even if they don't have a telephone number, they can still make outbound calls. We'll set the Caller ID to be whatever number you like.

To summarize, the number of extensions you need depends on the size of your business and the number of people who will need telephones. If you have questions about your extensions, or would like more information, please contact NWVOX Support at 1-877-208-9710, or send us an email at

For an overview of special extensions, please see the article A Look at Special Extensions.