Using Analog Phones

Home » Asterisk Users » Using Analog Phones
Asterisk Users 7 Comments

Hi folks,

A client wants to keep their old Inter-Tel KTS analog phones for budget reasons. Two questions:

1. How could they use these with FreePBX?
2. Would they be losing any features that they currently have with their analog PBX?


Noam Birnbaum Mac Daddy
877.luv.macs x666
tweet @noamb

Tech support

7 thoughts on - Using Analog Phones

  • You’d need an ATA or an analogue card. And how well they work, depends on if they are ‘true’ analogue, or have extra digital pairs etc.

    You’d need to find out what features they have on their PBX, and compare this to FreePBX.


  • dSBuZWVkIMKgYW4gYW5hbG9nIHRlbGVwaG9uZSBhZGFwdG9yIHRvIGNvbm5lY3QgeW91ciBhbmFs b2cgcGhvbmUgd2l0aCBzd2l0Y2ggaHViLiBidXQgdGhlIGRldmljZSBpcyByYXRoZXIgZXhwZW5z aXZlLgoKClNlbnQgZnJvbSBTYW1zdW5nIE1vYmlsZQoKTm9hbSBCaXJuYmF1bSA8bm9hbUBtYWNj ZW50cmljc29sdXRpb25zLmNvbT4gd3JvdGU6CgpIaSBmb2xrcywKCkEgY2xpZW50IHdhbnRzIHRv IGtlZXAgdGhlaXIgb2xkIEludGVyLVRlbCBLVFMgYW5hbG9nIHBob25lcyBmb3IgYnVkZ2V0IHJl YXNvbnMuIFR3byBxdWVzdGlvbnM6CgoxLiBIb3cgY291bGQgdGhleSB1c2UgdGhlc2Ugd2l0aCBG
    cnJlbnRseSBoYXZlIHdpdGggdGhlaXIgYW5hbG9nIFBCWD8KClRoYW5rcyEKCgpOb2FtIEJpcm5i YXVtCk1hYyBEYWRkeQpodHRwOi8vd3d3Lm1hY2NlbnRyaWNzb2x1dGlvbnMuY29tCjg3Ny5sdXYu bWFjcyB4NjY2CnR3ZWV0IEBub2FtYgoKVGVjaCBzdXBwb3J0IOKAlD7CoDg3Ny5sdXYubWFjc8Kg b3LCoHN1cHBvcnRAbWFjY2VudHJpY3NvbHV0aW9ucy5jb20KCg=

  • Via so-called Analogue Terminal Adaptors (ATAs). These are basically a SIP
    phone with an FXS interface instead of a handset and keypad.

    Alternatively, up to four analogue phones could be connected through something like a TDM400P fitted with four FXS modules.

    Note that ATAs are not cheap! Replacing the analogue phones with SIP phones might actually work out less expensive.

    This is very unlikely. Check the feature set to be sure.

    Asterisk is basically a telephony construction kit; so the chances are, any feature they seem to be missing can be added, either in the dialplan or with an AGI script.

  • I have done a good deal installations where analog handsets, headsets, or many faxes just made sense. I have used T1 cards to connect to 24
    port channel banks to provide true analog dialtone.

    I have also used SIP based channel banks with great success but never bothered messing with the fax issues.

    FreePBX should give you way more functionality than their current PBX, sometimes it just takes a little creativity and doing things differently. Always get the details of what they currently use. An admin assistant or secretary is usually the person that knows what bells and whistles everyone uses. That is the person that you really want to befriend for a smooth implementation.

    Finally, I have installed a handful of Inter Tel/Mitel PBXen along the way, and the phones I installed were infact digital and proprietary. Check the model number of the phones to see if they are truly analog, which I doubt. In that case, you can still use a FreePBX box, but you are going to have to integrate it with the Inter Tel, I usually put Asterisk in front and just timeout your ring to VM a little bit shorter on the Asterisk box than the Inter Tel.

    With phone prices what they are, and a very good Polycom (or whatever you like) SIP phone so cheap, I would seriously consider ditching the phones if you find that they are digital.

    Thanks, Steve Totaro

  • Thanks to all who applied. I found out that their Inter-Tel phones are connected to an Inter-Tel Axxess box-thingamadoodle (that’s a technical term). Inter-Tel was purchased by Mitel in 2009 so there’s no support left. I think I’m gonna recommend they use IP phones or a different VoIP consultant

  • switch hub. but the device is rather expensive.

    GrandStream 8 port ATA is about $200.00 which is much less than a single new SIP phone. Much much less expensive than new. The Cisco ATA is about
    $400.00 but may only give 4 analog telephone ports (FXS). reasons. Two questions:
    analog PBX?