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VoIP with Analog PA Systems and Visual Alerts? 27

An anonymous reader asks: "We have an Asterisk/SIP based VoIP system at work, and I've been tasked with adding some features. First, we need to be able to patch it into our analog PA system at several office locations. I've managed to hack together a polycom phone set to auto-answer, and a custom cable from the handset to plug into the PA. This works well enough, but the phone really isn't designed for it, and I find that it just isn't reliable. What I need, and haven't been able to find, is a simple SIP enabled device that will auto-answer, and has line-out that I can feed to the PA. That way, if a user calls one of several numbers, they get tied into the associated PA system, or maybe even all PA systems at once. The next piece of the puzzle is a visual alert so that when a SIP phone is ringing, a light flashes. This will allow people in a loud environment to still know the phone in the office is ringing." Any ideas as to how this could be done?
"Ideally this would be just another SIP device that I could have Asterisk dial the same time the office phone gets dialed. The analog version of these is easy to come by, but I haven't been able to find a networked SIP version anywhere.

I'm not above building my own if their are some basic SIP device schematics out there, but I'd rather find a commercial solution and be done with it. Any help will be greatly appreciated."
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VoIP with Analog PA Systems and Visual Alerts?

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  • ATA (Score:1, Interesting)

    by Anonymous Coward
    In order to provide the likes of flashing lights when the phone rings, isn't it just a case of using a Grandstream (or other) ATA to get you into the analogue world and then doing whatever you'd normally do there?
  • Google is good (Score:5, Informative)

    by Marxist Hacker 42 ( 638312 ) * <seebert42@gmail.com> on Monday September 18, 2006 @05:51PM (#16134367) Homepage Journal
    Looks like These guys [sipcenter.com] have pretty close to your shopping list covered- they even have a phone with auto answer that has our friend, the standard 2.5mm universal headset port, which could be used for hooking up to the PA system.
  • Visual alert (Score:3, Informative)

    by alienw ( 585907 ) <alienw...slashdot@@@gmail...com> on Monday September 18, 2006 @05:53PM (#16134383)
    Well, the visual alert part is pretty easy. Buy an ATA and a visual alert thingee for a regular analog line (I believe Radioshack and many online places sell them). The PA thing is harder, and I don't know of any devices that could easily do that.
  • VERY EASY (Score:4, Informative)

    by Helix150 ( 177049 ) * on Monday September 18, 2006 @05:59PM (#16134416)
    Buy a two port ATA. If you can't find one, I can't help you.

    Connect port one to a Viking Electronics Paging Controller [vikingelectronics.com]. When you dial the ATA port one, it will answer. Connect it's output to the paging amp. Viking also makes other models, some with built in paging amp.

    Connect port two to a Radio Shack Phone Flasher [radioshack.com].

    When you need to page, have * dial ATA port one.
    When you want a call to flash the light, dial ATA port two along with the other phones. Remember you only want it to ring, not answer.

    For paging you can also use a hacked up Grandstream phone, I have heard good results with these.
    Or use the server's sound card.

    Hope that helps!
    • PARENT IS INCORRECT (Score:4, Informative)

      by mo ( 2873 ) on Monday September 18, 2006 @07:44PM (#16134939)
      Most ATA devices do not have proper disconnection supervision on incoming calls. (google for CPC Duration on Sipura ATAs).
      This will cause problems as the ATA will not hang up the Viking controller when the call ends.

      My recommendation would be to swap out the ATA for a Sangoma or Digium FXS card and use a Bogen TAM-B or somesuch paging controller.
      The FXS card will do the right thing and hang up when the call is ended.

      Another option is a Grandstream GXP-2000 which has a 1/8 stereo jack in the side.
      Rumor has it that the latest GXP-2000 firmware does the right thing on hangup but I haven't tested that. The old firmware played a beeping busy tone endlessly until you hit the speakerphone button to hangup.
  • by Anonymous Coward
    Do you know what google is? honestly?!

    2 seconds...bam! I searched "VOIP paging"

    http://www.twacomm.com/catalog/dept_id_1050.htm?ut m_source=GGL&utm_medium=cpc&utm_term=voip+paging&u tm_content=Paging&utm_campaign=VoIP [twacomm.com]

    Good lord...
  • by cfoster611 ( 219409 ) on Monday September 18, 2006 @06:16PM (#16134495) Homepage
    What I used to do for my own PA system is use the sound card in the old PC I had running Asterisk.

    Use chan_oss or chan_alsa, and the Asterisk box takes care of the automatic picking up. It works great.
    Grab a spare PC, install asterisk, do a IAX channel to it and it think you'll find it better, have more control.

    The line in my asterisk setup was :
    exten => 310,1,Dial(Console/dsp,10,A(tone11)) ;;intercom

    This dialed the Console, or sound card, then played a tone right before the channel went live, as a warning tone.
    There's tons of applications for this. I used to have a program that somebody made that would say the incoming callers
    Caller ID name and number over the intercom as the phones rang. Plus, you could dial in mp3 requests and i'd use mpg123.

    Good stuff. I'd recommend going this route. you don't need a huge, fast new PC, I did it with a P2 450, and it sounded great.
    • Re: (Score:3, Funny)

      by colenski ( 552404 )
      crap moderated this post incorrectly so I have to post to undo the mod sorry
    • by LWATCDR ( 28044 )
      "There's tons of applications for this. I used to have a program that somebody made that would say the incoming callers"
      Shouldn't be hard to write an application that would blink a light of some kind. X10 could even be hacked to do it. Sounds like a project :)
  • We have an FXS port connected to a viking paging module that is addressable as an extension. You can use cat 5 networking wire but have rj11 type devices attached to it and put the paging amp on that if you like. We use Fonality PBXtra and polycom phones mostly. Aastra and a few others will have paging available in the next firmware release so a cheap phone wall mounted might solve your problem.
    • AAstra intercom has been available for a while, as I recall it was added in 1.3 and they recently released 1.4. It also now supports ringtone by sip header (also in 1.3).
  • PC == SIP device (Score:1, Informative)

    by Anonymous Coward
    Is your Asterisk server a PC of some sort? Or is there another PC (or laptop) that you could use for patching to the PA system? I would think you could get an SIP software phone package, and hook the pc sound card output to the PA system. Configure the SIP soft-phone to auto-answer (I think that one of the many SIP software packages out there would have an auto-answer feature), and you have your patch.

    The flashing-light thing sounds a bit trickier, but I bet you do something like the following: get an SIP-t
  • We have our Console for Asterisk as our PA output here at our office. It is ghetto rigged, but it has been working a year. You can cut the end off a set of speakers (leave enough wire to work with though), then splice it onto a pair that runs to your PA (depending on the type of PA of course). Just adde the console to that call/conference/meetme/whatever, and you will be speaking on it.

    If at multiple locations, just have an asterisk box at each location with a sound card and do the same.
  • We're using Linksys SPA-941 phones at my work and they have a visual ring indicator (red light bar at the top which flashes). If you're using soft phones, just find some software that'll give a visual indicator.

    As far as the PA system, get a phone that's compatible with Asterisk's paging/intercom support, then just tap into the phone's speakerphone wires (easy to tap mono analog sound signal, may need to add some hardware to adjust for signal strength) and route that into the PA. Or use the headset port,

  • Being able to flash a light when the phone rings shouldn't be difficult; particularly for anything designed for a workplace, where ADA Disability compliance may be mandated by law.

    But this made me think of the usual ways deaf persons access the telephone, such as TTY machines. Do most office VOIP solultions support plugging in a standard TTY? a deaf person may be able to use e-mail; but the person they are calling, or is calling them may not have access to e-mail at the time they call.
  • What I need, and haven't been able to find, is a simple SIP enabled device that will auto-answer, and has line-out that I can feed to the PA. That way, if a user calls one of several numbers, they get tied into the associated PA system, or maybe even all PA systems at once.

    I sure hope you've got a air tight way to screen out telemarketers.

    --MarkusQ

    • by mibus ( 26291 )
      I sure hope you've got a air tight way to screen out telemarketers.

      I believe the submitter meant calling an internal (extension) number.
      • by MarkusQ ( 450076 )
        I sure hope you've got a air tight way to screen out telemarketers.
        I believe the submitter meant calling an internal (extension) number.

        You're probably correct. But it would certainly be an amusing failure mode if not (in an "Office Space" sort of way).

        --MarkusQ

        • I recall reading a story many years ago about some young disgruntled Fred Meyers customers, who, upon realizing that the store's paging unit was simply attached to a local extension of the store PBX, would call the store periodically and ask to be transferred to that extension. Eventually, they got somebody who didn't realize what they were doing, and, once transferred to that extension, they proceeded to lambaste the store and offer their opinions over the paging system. Worse, once connected, there was
          • Indeed, I worked at a company that had the paging extension on a DID, which could be dialed directly from anywhere on the planet. If you knew the code to activate all-zone paging (11), you could talk to the whole building. They figured that out the hard way after somebody kept randomly dialing in and playing Beavis and Butthead through the speakers. (This was pre-Office Space.)

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