New to VoIP. Multiple extensions per phone? Necessary?

I’m working on a 20-30 phone deployment. I’m conflicted whether or not to recycle the old pbx extension numbering scheme that was per-floor based.

11xx for floor one, 12xx for second floor, 13xx for third floor. etc.

What happens if a user moves to a new floor? Should their extension change?

I’m toying with the idea of keeping this old extension numbering scheme…associating these on a per-phone basis (phone’s don’t move around the building, people move around). However, I would also create a new block of numbers for per-user extensions that will follow the user as long as they are an employee?


I don’t think it matters. Another way to keep track of where phones are physically located you can also do it through their DNS assignments via your router.

Extension numbering schemes by floor number might make sense if there is a reception desk on each floor. You could do x100, x200, x300, etc.

Back in the olden days, it was hard to reprogram an extension whenever someone moved. It could be done, but it wasn’t common and the PBX guys would sit and whine and complain for days while he or she did it. The instrument was hard wired to a desk and the jack at the desk determined the extension number.

With FreePBX, SIP, Network Phones (or even Softphones) and the idea that “I’m taking my phone with me”, they just unplug the phone and move it to their new desk. Because of that, the initial assignment could be “floor based” but would eventually become “my extension”. You can assign several extensions to a single instrument, and you can forward extensions to other extensions all over the place.

If it was me, I’d assign a three-digit extension to an instrument and use that as the primary number. After that, you can assign virtual extensions using the old numbering scheme if the client still wants to use the old numbers. As people get used to have a 3-digit number that always rings “Joe”, they’ll start using the four-digit numbers less and less, and eventually, the four-digit numbers can be retired.

It depends on how much monkeying around with the system you’re willing to do.

How many systems I’ve made, i learned that there’s no simple answer what extension number range to use.
Some like 4 digit extensions, some want separate ranges based on floor, some want based on the department and so on…
I learned to let the customer decide, and of course provide some tips to help them make a proper decision, this of course involves planning - like you said, an employee moving from one department to another or to a new desk etc. How will you work this out?

In some cases where a user is switching desks we often ask to physically swap the phones, but in cases where we can predict the user will plun in the Lan cable in the PC port, we swap the MAC’s in EPM and reboot both phones.

We’ve had some customers who wanted completely different extensions from their Old PBX, so while migrating we made with some custom scripting that when a caller enters an Old Extension it plays an announcement which says that this extension was changed to [105] so callers will learn of the change.
In some cases, we added the old extension as a Virtual Extension that goes to the new one.

And the game goes on…

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