Quick Question - Intercom style phone system?

Hello all.

I know the annoyance of a newbie asking silly questions, after looking for answers I found it not a straight forward “yes it can be done” or “no you idiot”.

The question I have is… I have a radio station, I am in the office and if i wish to speak to a presenter in the studio am i able to set up a FreePBX onto a computer. Then connect a phone in the studio and one in my office, just to be able to call the extension.

I DO NOT wish to make any outgoing calls or nor to receive any in-coming calls.

I literally just want it set up to ring extension “100” or whatever and they able to call extension “101” to call me in my office.

So, can this be done with just FreePBX and 2 IP phones. Or do i still need a SIP or a provider.

Thank you for reading.

Yes it can be done…but it’s an overkill. There are simpler solutions out there…

What about direct dialing without a pbx?

Here’s another source

Thank you Charles.
Both information you provided are very helpful!

We are hoping to eventually use the IPPhones for incoming and outgoing.
So was going to hopefully have the PBX service in place with phones on extensions for the timebeing and when we are ready to go across to external calls it will be simple to set up. ( in theory )

Just to confirm once we are ready to go to external calls, we will then need a provider to transfer the calls?

Thank you for the advice and help so far!

You can set up a freePBX server just with two extensions, yes. Later on you can configure a trunk (connection to your provider) with an outbound and inbound route.

Thank you Charles for dumbing it down for me!


A number of VoIP providers include basic PBX features (voicemail, IVR, ring groups, call forwarding, etc.) with their service. If a simple system is adequate for your needs, you won’t have to learn, install and maintain your own PBX.

Callcentric, Anveo and VoIP.ms are some that you might consider. These providers have a monthly charge for each number and a per-minute charge for calls. If you have no numbers and don’t make any calls, your monthly bill is zero and you can use it as an intercom at no cost. With Callcentric, you can select the “IP Freedom” plan and run your intercom without making a payment. The other two require an initial deposit (I believe $25), but if you don’t incur any charges that will last forever.

There are usually monthly charges for 911 access, which you could avoid by stating that your usage will be outside US / Canada. However, in an emergency a visitor or employee might grab one of your phones and call 911, not realizing that it’s just an intercom, so you should consider paying for it to work properly. Likewise, if you do install your own FreePBX, consider having a trunking provider so 911 works.

And it is required by law in most jurisdictions that there be a huge notice that the phone cannot dial 911.

Replying to both of you.

I am in the UK, I am currently installing FreePBX right now.
Hoping I can get it working correctly!

Thank you for the advice.

Just in case :wink:

To add phones, do i need to buy the Endpoint Manager?

I thought this would be free :frowning:

Depends on your phones…for Sangoma D- and S-series phones it’s free. But actually you dont need the EPM. What phones do you have? Do the phones have a Web-GUI? If yes, you just add the address of the freePBX server and the username and password. In freePBX you just create two new extensions (pjsip or (chan_)sip). That’s it…
Some phones can connect to a LDAP server…if your phones can do it, you have a central phonebook. Otherwise you have to add phonebook entries on each device separately…

I currently have 2 Cisco phones I am waiting to connect to the server. (waiting for a PoE switch)

Will this be possible to work with the FreePBX?

Also, Once a potential listener has connected to the phone, am i able to transfer it to the PC like a phone software (i believe they call it a SoftPhone)


Yes you can transfer calls from a desk phone to a softphone if you want.

What model of Cisco phones are they? If they are the SPA series, they are easy to connect, otherwise they will not be easy as the others are meant for Cisco’s platform.

Oh really, they are CP-7942

Is this going to be a problem?

yes, this is the mother of all problems :wink:
This type of Cisco phone uses a Cisco protocol. They offer alternative SIP firmware though…at Cisco. Maybe it is already installed?
These phones are the worst choice for a freePBX beginner, because you have to apply several fixes…to make them work…

Explains why they are so cheap !

Yes…excellent hardware, but poor SIP support. I still use Cisco 8961 phones with freePBX at one place.
I patched Asterisk (Asterisk Cisco BLF patch), configured an openLDAP server (for a central phonebook) etc
Took me years…literally…but has been working perfectly.
It is an interesting project…Cisco&freePBX…but a no-go for beginners.

And you would have to buy the Endpointmanager…to finally find out that it just gives you very basic functionality…with Ciscos.

Well, I now have a headache!

I’m waiting for my PoE switch today, I’m not sure what to do now. lol

I guess I need to go look at getting new phones bought.

Unless i give it my all to get them working… but like you said as a beginner, I will be way out of my depth.

You could try to use the EPM, but as I said, it gives you just around 20% of features. The BLF (busy lamp) wont work, no phonebook etc.
The Ciscos require a xml config file in the tftp directory of you freePBX server. The EPM is supposed to create such a file. Check the compatibility list of the EPM. Is your phone listed?

The other problem is…
Which firmware is installed on your phones? SIP? You would have to point the Ciscos to the IP address of your server to pick up the config file.