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Turning Your PC Into a LAN-based Intercom? 25

AugstWest asks: "With all of the VOIP projects all over the net, and more and more of us geeks installing machiens in every room in the house, it hit me that we've got all the wiring and hardware necessary for a full-house intercom installed. Software, however, is another story. None of the VOIP projects I've been able to find can be easily adapted to instant-on lan voice communications. With a microphone hooked up to all of the machines throughout the house, shouldn't it be simple to set up instant-on voice software? I've scoured the net for it, does any already exist?"
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Turning Your PC Into a LAN-based Intercom?

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  • speak freely (Score:5, Informative)

    by rplacd ( 123904 ) on Monday November 18, 2002 @03:06AM (#4695047) Homepage

    Speak Freely [] should do all you need. Plus, it's cross-platform; I have it on both my FreeBSD and Windows machines at home.

    • Re:speak freely (Score:4, Informative)

      by gleam ( 19528 ) on Monday November 18, 2002 @05:22AM (#4695484) Homepage
      teamspeak now has both linux clients and servers, which would likely work on freebsd (via linux emulation) as well. i know for a fact the server does.

      the main advantage of teamspeak over speakfreely is that, aside from having better quality low-bitrate codecs, it automatically mixes speech on the server.. speakfreely doesn't, it simply reflects everything, and teh clients do a horrible job of mixing the voice streams. if two people talk at once in speak freely, the third person can't understand either of them.

    • Got it in one.
      Just leave the output program running on all programs pointed at one box with reflector running. Then a little script that starts the mic program and points ether at a spacific other box or the reflector for all the boxes. Would work great for a LAN.
  • by Pyromage ( 19360 ) on Monday November 18, 2002 @03:24AM (#4695098) Homepage

    nc -l -p 5000 > /dev/dsp


    cat /dev/dsp | nc hostname 5000

    You probably want something a bit more... robust than this, but hell, what do you want for 2 lines of bash? :)
  • Wat about wireless speakers has it? Can it be done
  • Why not utilise OS X's speech-recognition software? I am pretty sure that it is scriptable via Apple Script.


  • by Anonymous Coward on Monday November 18, 2002 @05:14AM (#4695462)
    Throw one in every room ;)
  • Security (Score:4, Funny)

    by theedge318 ( 622114 ) on Monday November 18, 2002 @06:47AM (#4695688)
    I hate to be a nay sayer about neat cross platform networking applications ... but as a Windows user (and a computer user in general), I understand that my computer is only secure when I remove it from a power source.

    Therefore, I would not be inclined to install software that would allow people to listen in to conversations in my house.

    If I had kids I definitely wouldn't run the software ... just in case they accidently managed to get a connection to "bedroom noises" ...

    My parents had an old style intercom ... and I found out that by pushing the "End Transmission" Button when the line was closed, you were actually able to listen in to every other room in the house ... THANKFULLY, I can still say that I believe my parents are "celebate" :-)
    • In a previous job we all had to use NeXT's... and all had a builtin microphone... the boss would hold closed door meetings all the time and one of my collegues wanted to know what was going on so as the sysadmin he'd turn on the boss' microphone, send the output over the net to his machine and out his speakers.

      Came in handy when he started talking layoffs :)
  • Yup, everything on 100BaseT, or even 1000BaseT (GigE Copper). Sure would simplify home cabling, wouldn't it?

    Ever wire a house for voice, video, data? Well, there's a rather standard way of doing it and it involves two four pair cables (Cat5e, generally, though in the "old" days, if you were penny wise and pound foolish, you'd run one Cat3 and one Cat5, or worse, one quad "Jake" and one Cat3), and two RF cables (RG-6/U, preferably quad-shielded).

    One of the quad-pair is used for data, the other for phone (some of the more complex phone systems actually need all 4 pairs); one of the RF cables is used for distribution from the headend, and the other for modulated distribution back to the headend, to distribute your DVD throughout the house.

    It's supposed to be the most cost-effective way of doing things: cheaper to RF-modulate an analog signal than do real-time MPEG2 encoding to stream over IP, right? Same for the phone stuff, though, as the original query hints, not out of the realm of afordability to do it over IP. And all that cable! Do you know how thick a bundle of 2xCat5e and 2xRG6/U is? About 3/4-7/8 inch. It's a real pain to retrofit into an existing house. Been there, done that. Wireless data networks start to look real attractive.

    Now, you can get products like SpeedWrap that add an extra jacket (and some even include Fibre), which makes deployment a bit easier, but the cable costs about double what individual cables do (still, if you're paying for installation, it can be worth it).

    Yeah, it would be real nice to do it all over IP, and thus, one 100BT or GigE network connection.

    I've often thought of a "per-room" interface box, with network in, and telco, intercom, digital audio, and video outputs and possibly digital audio and video inputs. The idea is to interface to legacy equipment (like standard handsets, intercom speakers, stereos, TV's, etc), with one little wire snaking back to the headend. Computers, of course, connect directly to the network. You might want to splurge and have several nets: entertainment, data, and DMZ data. Such things would be a real hacker's dream to design, build, and deploy.

    The kicker, of course, is cost. A phone and a bit of wire is way cheaper than this kind of tech, which requres, effectively, a fairly powerful computer in each room to be networked. Gigabit ethernet switches don't come cheap. Start running MPEG2 video around your home lan and the ??AAs will be all over you for "infringement". Still, Moore's law being what it is, in about ten years, such things could be made as cheap as doughnuts.

    Yeah, this went off-topic, and didn't provide any tech solutions for IP-intercoms, but it does warrant examing the bigger issue of putting all of a home's digital and digitizable traffic on a LAN.

  • by ericski ( 20503 ) on Monday November 18, 2002 @04:08PM (#4700196)
    1. Get up and go talk to them (unless you have a really big house.

    2. Do what I do. I page my kids via the yell command and they usually reply via the what? response. This isn't always going to work because of collisions, crosstalk, and limited bandwidth but it doesn't cost that much, is cross platform, and very portable.
    • I use this method as well. However the problem I have with the system is interrupt latency. Quite often interrupt response times could be as high as 1 minute. Even after repeated 'yell' commands, (especially when their faces are glued to the TV).

      Sometimes the 'demand' and 'ultimatum' commands don't even get through.

      Actually the problem could also be due to packet filtering. It is possible that they have a rather neat packet filter that filters out all those commands.

      Oh well...
  • XMMS-Shoutcast? (Score:2, Interesting)

    by csmiller ( 315238 )
    You could use Shoutcast (or other net radio program) as the source, and XMMS on each machine. xmm-shell can be used to stop/start xmms when the stream ends, if the streaming protocols don't support this. I envisage a program than looks for the presence/absence of a file, and then resumes/pauses XMMS appropiatly.
  • I have seen net meeting used for that very purpose about 2 years ago. its already on the comps, so why not try it?
  • Gamers have been using a utility called Roger Wilco for some time to do basically exactly this over the Internet. Windows-only, I think.

  • I don't know if anyone else brought this up, but you can get intercoms at Radio Shack. All you need is a phone jack in each bedroom and a power source. I think they're $50 for two. They also are perfect for doubling as a baby monitor (albeit wired).

  • [] has a pretty comprehensive list of the softphones that are currently available. A number of IM clients (Yahoo, AIM, MSN) also support voice chat, but some of them had trouble going through NAT the last time I checked. The IM clients also require about two or three clicks before you can start talking to each other, so they might not be the easiest solution for intercom usage.

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