Users and Extensions


I have what may be a dumb question. How many extensions for a user? We have some users setup with multiple extensions: Office desk phone (hardware handset), home phone (hardware handset), office soft phone (PC) and mobile soft phone. That is 4 separate extensions for this particular user.

Is this the recommended way to configure a FreePBX? Seems complicated and also a management headache. Additionally tracking down users configured like this is difficult for callers.

Any suggestions are appreciated.

There are a couple of ways to do that:

  1. You can use the “last to log in wins” approach. Doesn’t work well, but it’s entertaining until you get fired.
  2. If you are using Chan-SIP, you just each user a three-digit extension “family” and add the 4th digit to make their extensions unique. The three digit code becomes their ring group, and their four phones ring whenever anyone calls the 3-digit RG.
  3. If you are using PJ-SIP, you can have multiple devices logged into an extension. You increase the “extension limit” to 1 or 2 more than you need for the actual number of extensions you are using. There are limitations on this one too, in that sometime you get a situation where only one or two of the phones (out of four) will ring, but it does seem to work,

Only in places of the code that were not updated to dial with the pjsip logic. Notably park ring back and whatever hook FOP2 uses. Those calls just ring to the first contact.

1 Like

With a modern FreePBX install, all of your extensions should be PJSIP. So this means the only real answer is to do as @cynjut mentioned in his option 3. Doing anything else is just hacky if all that you want is for all of the phones to rung when a user gets a call.


To add. Phone Apps Hot Desking allows you to have a single extensions and log in from different locations.

Thanks for the suggestions. We are using chan_pjsip.

Wouldn’t it be best to have 1 extension number and share it among all their devices and soft phones?

That is what option 3, above means.

@sorvani thanks. One part was not clear to me:

How do I increase the “extension limit”? So if a user has 4 extensions currently I would increase to 6? Why is this?

How does voicemail work in this situation? It seems to me that voicemail is extension specific and not user specific, or am I mistaken?

You’ll be able to get into your own voicemail once you are logged in.

In PJSIP parlance, the configured extension is the Endpoint, and each registered device is a Contact. To register multiple contacts, you must edit the Max Contacts parameter on the Advanced tab of the extension so it’s => the number of devices you wish to register.

I found that setting, thank you. What is unclear to me is that earlier you mentioned that I should set this number 2 higher than what I actually need. So if 4 Endpoints (devices and soft phones) are currently used I should set this to 6. Why is this?

I see, this app runs on the device. I assume this only works with Sangoma or Digium phones. We also have some SNOM and Cisco phones. Can this work with soft phones like Bria 5?

Not my recommendation, not strictly necessary but not a bad practice.

Phone Apps support is documented here:

Cool, thanks. I am changing one extension now to test.

Only one of our phones is supported (D65) but I did kind of like that idea. More important is that I may be able to reduce the number of overall extensions we currently have by using Max Contacts.

I changed one extension to Max Contacts = 8 and modified 3 of the 4 phones (Cisco 8841, Cisco SPA504 and Digium A30). The original phone using this particular extension is a Digium D65.

Some Results:
After some test calls from outside two of the phones - D65 and SPA504 - do not light the voicemail waiting indicator.

Listening to the voicemail from the 8841 resets the message waiting indicator on the 8841 but not on the A30.

Making another call from outside and listening to the voicemail from the A30 does not extinguish the message waiting indicator on the other phones so I presume that the message waiting feature is unaware when multiple devices are connected to the same extension.

Otherwise setting Max Contacts seems to work well. Would be perfect is all the devices were able to know when the voicemails were listened to from one of the other phones.

That is a subscription, no different than any other BLF. Check your phone settings. There is only a single Subscription for each extension.
There is a setting in the advanced tab of the extension about how Asterisk notifies.

I see that the extension I am testing with is already set to MWI “Auto”. I am not sure what I should be looking for on the phones themselves. I am configuring all the phones via their web interfaces.

It depends entirely upon what you mean by “extensions” and “user.”

If you are using chan_sip extensions, you can only have one device registered at a time to each extension. So, Extension 101 can only have ONE phone connected to it. Extension 102 can likewise only have ONE phone connected to it.

The FreePBX devs developed a number of work-arounds to allow you have to multiple phones that appear to have the same extension, but none is perfect. First, there was “device and user mode,” which was the most promising, but which the devs continue to state is “not supported” or something like that. I’m not going to go into any detail beyond that.

The second work around is to set up each phone with its own extension number, but then have a ring group that rings all the phones. You’d also set the internal caller ID field for each phone to be the ring group. You’d also set up only one of phones with voicemail, and then use the mailbox field to cross-reference the other phones to that extension’s voicemail so that everyone would show the contents of that voicemail box. This is the easiest method, but it won’t support force all internal auto answer if you use that feature.

Pjsip extensions are supposed to support multiple devices registered to the same extension number at the same time, but I’ve been told that the SIP headers will get split if you have too many and they go out over the public internet. I don’t know much about that otherwise.

If by extensions and users, you are referring to how many different extension numbers can be registered to a single phone, then the limit is based upon the capabilities of the phone.

If you want multiple extensions to share a single VM, that’s relatively easy.

First, create four extensions, i.e., x. 101, 102, 103, and 104. Enable VM only on extension 101. In the “mailbox” field of x. 102, 103, and 104, change what’s there to “[email protected]” Now, x. 102, 103, and 104, will show the contents of x. 101’s voicemail. Program the VM key on x. 102, 103, and 104 to dial *98101.

Voila! Now all four phones share a single VM, and check the VM, and will show no VM when the mailbox has been emptied.