Multiple extensions on phone and call routing questions

First, let me say that I am a newbie and this is my first post. I’m
hoping someone can help me. I have spent lots of time reviewing module
User Guides and web searches and I’m stuck. I apologize in advance if my
use of terminology is incorrect or ambiguous.

For my system, a home office with multiple businesses, I would like to support multiple extensions on a set of phones. I have multiple incoming lines, DIDs, that I want to use direct incoming calls to specific groups of phones. I would like these calls to ring on all phones in a group (or at least
have the ability for a user at the phone to know a call is coming in and
from what number or extension). If there is no answer I need to use a
specific recorded voice message as a destination based on the DID.

I know I can use Ring groups to get the calls to ring on multiple phones.
But, since I need to identify the incoming number, it appears that I
can’t use CID prefix to tag the number. Also, it appears that with Ring
groups I can’t selectively set the destination. This is important
because for the no answer condition I want to have a voice message
specific to the incoming number.

I thought of using an IVR as a destination for different inbound routes that would use a CID prefix. But, getting the call ring on multiple phones and with specific voice messages still doesn’t seem to work. in fact, this approach may be overkill if I don’t need to. But, I definitely would consider it if I could get it to support all the things I need.

I’m using Polycom multiple line phones that support private and shared lines. Since I really don’t understand these two choices I haven’t been able to figure out if one of these modes will help me support what I need.

Thanks in advance for any suggestions or clarification that will help me with this system.

Having done your research, you’d know that there are lots of ways to solve the problem you are having. The problem is that the solution is different based on several factors that you did not provide and at least one issue that makes what you want to do that much harder. We’ll start with the issue:

  • You are trying to do something we call “multi-tenant” with a phone system that doesn’t do it very well. The handling of the incoming calls part works, but after that, the problems get harder and harder, especially as you add more and more businesses.

From here, your solution set becomes needs based.

  • The number of phones, ring groups, DIDs, and Businesses are all important considerations. In accounting, we have a concept called “fixed and variable costs”. The first DID is your Fixed Cost, but there are economies that come into play as you add more Variable costs (more DIDs, etc.) The cost here is complexity - the more of each of these you have, the more complicated your configuration needs to be.

  • Different versions of Asterisk and FreePBX offer different levels of support for different options. Since you haven’t even told us for sure that you’re using FreePBX, let alone a version number, it’s hard to make suggestions and recommendations.

  • Your “ring group” strategy may need revisited. If ring groups are not meeting your needs, you might need to implement queues.

  • Changing the Caller ID on an inbound call to include a CID Prefix is simple. Also, an IVR isn’t going to help you with a Caller ID prefix - you set that on the inbound route.

  • When your ring-group fails, you should be able to set up a “destination if no answer” at the bottom of the screen. You can send it to an announcement that is then tied to a voicemail, or some other destination.

So, basically, with the exception of Multi-tenant hosting (which is really hard to do well in FreePBX), everything you want to do is a matter of looking at the options and figuring out which ones you want to use.

If you want more help, be specific, use examples, tell us what you are doing and why it isn’t working for you.

Thank you for your response.

First, I’m using FreePBX V12.

In terms of business needs and requirements, I’m trying to create a phone system to support 3 or 4 existing businesses as seamlessly as possible with respect to the handling of incoming calls. Each of these businesses were previously supported by separate phone numbers on separate carrier lines. Each of these numbers are what clients use to call each of the respective businesses. If a call comes in and is not answered, ideally I would like to have a voice message that is unique to the business that is being called. With the separate phones lines in the past this was easy to do.

I have been able to set up different extensions and incoming routes filtered by each of the DIDs that I have had ported to my FreePBx system.

For ease of use, I would like to have multiple extensions on multiple phones so that calls from more than one business can be answered on a single phone.

I have created a Ring Group that will allow multiple phone to ring where multiple extensions have been defined.

But, my final challenge is how to handle the “no answer” condition. Again, I need to have the voicemail that is played for the “no answer” condition be specific to the phone number/DID that is being called. Using the Destination field in the Ring Group definition it appear that since I can only specify one Voicemail message this is not possible.

My previous mention of using an IVR to front-end the incoming calls was a hope that this might provide a solution. But, using a Ring Group with and IVR to try to accomplish caller transparency still didn’t seem to be viable.

Four business = four basic setups.

Each inbound DID requires either a ring group or an IVR that points to the different parts of each business (For Hal, dial ‘1’, etc.). Each one is different for each business. I suggest you set up the extensions in groups (1000-1099 for the first client, 1100 -1199 for the second, etc.)

Each Ring Group needs an announcement. Each announcement is going to be specific to that business.

Each Announcement needs a Voice Mail box. Each Voice Mail Box is going to be specific to that business.

Remember what I said about “fixed and variable costs”. Getting the basic system set up for one business is straightforward. Adding additional businesses requires setting up a binch of stuff specific to that business.

After this little bit of basic stuff, the challenges start to get harder. For example, do you want the different businesses to be able to contact each other via their local extension numbers? Are you going to use Call Parking? (hint: that is a real bear to get right with more than one business in the mix). What are you planning on doing about Call Pick Up? Call Recording? User Control Panel?

There are lots of other things that end up being “community resources”, so maintaining the illusion that you have four phone systems for these four clients is going to get harder and harder as they get used to working with the system.

Multi-tenant is simple enough when all anyone wants is phones to ring. Adding the powerful parts of the system to the mix makes it a real challenge.

Thanks again.

In at least one of my testing iterations I thought I tried one of your suggestions and for some reason I didn’t get the results I expected.

For my initial purposes my implementation will have 1 incoming line/DID = 1 extension. Each business is one line or one extension. For each phone I want to have four extensions. When a call comes in for a business I would like it to ring or flash on all phones that have that extension defined. I have verified that on each phone I have multiple lines for each extension registered to my FreePBx server.

I defined individual ring groups for each DID=line=extension. However when a call comes in it only rings on 1 phone although the extension is defined on more than one phone.

My specific company voicemail works fine as I have it defined on the extension.

So, I thought I had my basic requirements satisfied. But, even though the line/extension is registered on multiple phones an incoming call only rings on one phone. I’m suspecting that it may be the first or last one registered. If it is, I didn’t think that this is the way it should work.


Extensions are separate from lines.

You have a line that comes in, it goes to a ring group. The ring group rings all of the extensions assigned to that ring group. One number per ring group isn’t a ring group - it’s an extension.

What you’re describing doesn’t make any sense. If each business has only one extension, why do you need four extensions per phone?

I’m not going to help you if you don’t explain what you’re trying to do. What you’ve described makes no sense whatsoever.

Answer the questions I asked in my original email.

  1. How many DID numbers?
  2. How many companies?
  3. How many phones?
  4. How many phones per business?
  5. How many people?
  6. How many voicemail boxes?
  7. If the voicemail box for the business set up for one of the extensions for that business?
  8. It sounds like you have four phones, four companies, and four ring groups with one phone in each. Why?
  9. What makes you think that registration order makes any difference anywhere?
  10. If each DID is going to a single phone, why do you need a ring group?

Unless you start given me specifics, we’re done.

I apologize for frustrating you. Certainly not my intention as I need all the help I can get. I started this post with an apology if my terminology was wrong or ambiguous I think part of the problem with my terminology is that I am using Polycom IP 550 phones. These phones are described as multi-line phones. From my reading of the Polycom setup documentation each SIP registration on the phone is referred to by Polycom as a “line” and there can be up to 4 lines configured. Based on my understanding, with these phones you register a “line” with an extension on the SIP server.

  1. 4 DID numbers

  2. 4 companies

  3. 4 phones

  4. In my home office I have 2 main office locations with one business phone in each location. I also have 2 other locations where I have phones that I want to be able to receive incoming calls from the businesses. In each location where there is a phone I want the phone to ring and be able to receive a call from any of the businesses.

  5. There are 2 people full-time and 1 person part-time supporting the businesses.

  6. 4 voicemail boxes – One for each business.

  7. Yes. Each business only has one extension

  8. Correct. I agree that a ring group with one extension doesn’t make sense. This was more or less an experiment to see if I could get all of the phones with the same extension to ring. I have tried this and I have tried using an incoming route that had a destination of an extension. But as I said before only one of the 4 phones that had that extension would ring.

  9. Don’t know if the registration order makes any difference. Pure speculation on my part in trying to explain why all the phone don’t ring. Only one. Trying to figure out what was different about that phone if they are all configured the same caused it to ring and not the others.Don’t know if the registration order makes any difference. Pure speculation on my part in trying to explain why all the phone don’t ring. Only one. Trying to figure out what was different about that phone if they are all configured the same caused it to ring and not the others.

  10. Agree Ring group is not necessary in this case. Can accomplish this by just pointing an inbound route to the extension.

I really hope I have better explained what I’m trying to do and why. I just need to know is it possible to have a phone that is configured to have connections to multiple extensions defined using FreePBX to receive incoming calls on each extension and have the phone ring on each phone where that extension is authorized? And, if so How?

Thank you for your patience and willingness to help. If I could ask the questions better I would. And in the future I’ll be careful to answer all questions I’m asked.

Yes, but to be clear, you can register the phones to your Internet Telephone Service Provider if you want to skip the local SIP server altogether. Not recommended, but you can do it.

If each of these numbers comes from the same provider, you need one trunk to talk to that provider, The number will show up in your system on the inbound route(s) as a DID from the trunk.

OK - this works fine. Each company will have an extension range in your system. it doesn’t matter to anyone but you what the range should be, but I’d start with 4-dogot extension numbers and start out with N000 for the main line for the business. So, “Carl’s Marbles” could be 2000 through 2999 and “Dan’s Cans” would be 3000-3999.

Each phone will have to have at least one extension number, with each “line” button potentially connected to a different extension. In a minute, we will find that you want all four phones to be connected to each business, which means 4 x 4 (16) possible connections (four extensions per phone, one per business, and four businesses).

In your home office, you have two offices with a phone each?

A location should have A phone, especially if your phones support multiple extensions. If your “home office” (which means you have an office in your home where I come from) has two desks, I’d go ahead with two phones, but I’d set them up so they were exactly the same, with the exception of the extension numbers.

This is the part where you’ve lost me. If your four businesses are actually four businesses, I don’t understand why the employees from each company would be answer the other business’ phones.

Your four businesses are four separate entities. Each of them has an incoming DID. I don’t understand why you want the businesses to answer each others’ phones.

Your four companies share three employees?

This makes perfect sense.

Each business should have one extension range. Your phones have extension numbers - the businesses have an inbound DID…

Company “A” has extensions 2000 -> 2999
Company “B” has extensions 3000 -> 3999
Company “C” has extensions 4000 -> 4999
Company “D” has extensions 5000 -> 5999

let’s assume each phone has four “extensions”. The “main phone” for Company “A” could be extension 2001. Assign it to one of your phones on “Line 1”. Company “B” would have a main phone of extension 3001. The Company “A” phone would have extension 3002 as the second line. Company “C” would have a main phone at extension 4001. The company “A” phone would have an extension of 4003 on Line 3. I’ve included a couple of tables below to lay out how each of your phone extension maps could be set up.

                     Line 1   Line 2   Line 3   Line 4
Company "A" Phone     2001     3002     4003     5004     
Company "B" Phone     3001     4002     5003     1004
Company "C" Phone     4001     5002     1003     2004
Company "D" Phone     5001     1002     2003     3004

                     Line 1   Line 2   Line 3   Line 4
Person  "A" Phone     2001     3001     4001     5001     
Person  "B" Phone     2002     3002     4002     5002
Person  "C" Phone     2003     3003     4003     5003
Person  "D" Phone     2004     3004     4004     5004

Now, each of your phones has lines associated with each business.

So now, you’ve got four extensions per business, one per phone. Put these extensions into ring groups - Company “A” is ring group 2000, which consists of extensions 2001, 2002, 2003, 2004. Do the same for Ring Group 3000, 4000, and 5000 for Companies “B”, “C”, and “D”.

As we move through this, it occurs to me that you might be trying to register each of your phones to the same extension without setting the system up to do that. With Chan-SIP, you can’t do that. With PJ-SIP, it’s possible, but you have to configure the extension definition to be able to register four extensions. The discussion above assumes you are using Chan-SIP.

For purposes of clarification, you should assume that only one phone line (assuming a four-line phone) can be registered to one, and only one, extension in FreePBX. This means that if you want four phones with one line each, you need four extensions. If you want four phones with four lines each, you will need 16 extensions.

I think I understand the technical part of what you want to do. The business part of it still eludes me, but that doesn’t matter.

In Summary:
In front of the PBX:
Four business - four phones - 16 lines (4x4) so 16 extensions.
behind the PBX:
Four DIDs -> Four Ring Groups (with four extensions in each) -> “On No Answer” goes to voicemail for extension 2001 for Company “A”, 3001 for Company “B” etc…

Sorry if I made it feel like pulling teeth for you to get the answers from me you needed to help. But, thanks to your persistence I have things working as I intended.

You are right regarding one of the major technical issues I was having. I was in fact trying to register multiple phones with the same extension. This is why the last phone that was configured was the only one registered and thus the only one ringing on incoming calls. I confirmed on the Asterisk log that the other phones were no longer reachable.

From a business perspective, I know it looks weird to want to share phones between businesses. But, again these are all home based businesses and for now my wife and I are the owner/employees with a part-time assistant. Having multiple business phone calls answered on the same phones is a convenience more than a necessity and certainly not a standard business practice.

I really, really appreciate all your help with this and I hope that there is something in this thread that someone else will find useful.