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Ethernet Intercom Systems? 24

Milo_Mindbender asks: "Has anyone seen an intercom system that operates entirely over Ethernet? Ideally, I'm looking for something like they use in TV and theatre, a self-contained belt-pack you plug a headset in one side and an ethernet cable (or wireless card) in the other. It needs to be controlable by a master computer that can link each user to any number of channels and change them around on the fly. A channel should be full-duplex and allow multiple people to talk/listen at once like a telephone conference call. This is for an entertainment venue where guests will use the system as a 'radio simulator' while playing multiplayer games and the staff will use it to help manage the facility. I'd prefer a ready-made system, but if you have suggestions for hardware/software that could be converted into such a system I won't complain!" While something like this would be a fun thin to do, why would someone use ethernet when radio-based (or, if you are careful...wire-based) communication products are cheaper and more robust?
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Ethernet Intercom Systems?

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  • It needs to be controlable by a master computer that can link each user to any number of channels and change them around on the fly.

    isn't so easy to do with plain old radio.. cool application, but likely VERY expensive..

    Actually, as long as you don't need a silly number of sets, it should be straightforward with a hybrid system that doesn't require ethernet. Make each headset a good-quality walkie-talkie with its own frequency, talking to the server. Have the server handle mixing of appropriate channels. The only missing piece is a card or set of cards with multiple audio-frequency analog inputs and outputs, and the phone companies have been using cards like this for years.

    You'd have to do a bit of hardware hacking to implement a system like this, but it's not terribly difficult.
  • First of all, no matter what the marketing people tell you, doing everything over IP is not the best solution for every idea out there. You have to ask yourself what you stand to gain by using an IP-based implementation;

    Where did the questioner say IP?

    This was a request for an ETHERNET based solution, my guess was that he is already planning on putting the cabling in, and using ethernet switches/hubs anyway. If he already has this communications infrastructure in place then why would he need to run different cabling. I can see the point in using an ethernet solution if he already has an ethernet network with the spare capacity. But nobody mentioned running TCP/IP over the top of it.

    Frankly I suspect a decent multi channel wireless system would be a much more reasonable use of the money. From memory Motorola [] Do a reasonable range of professional two way radios.

  • Several people now have dragged IP into this... The guy isn't asking for a TCP/IP intercom, he's asking for an Ethernet intercom. There is a difference.

    I'm assuming that they are already putting the Ethernet infrastructure in place, and figure that if they can use that for what they are doing then why put a second (or third or...) infrastructure in place.

    Most places are already using CAT5 throughout and running multiple points for the computer network and the phone system and... I've been in places like that (I still am) and just because it's Cat5 doesn't mean it's running IP.

    I don't have a solution using Ethernet, but a quick google search showed one or two possibilities...

  • Im too lazy to dig up any links right now but ive seen a setup that utilized limited spectrum 2way radios communicating via a receiver/transmitter unit connected to a computer. Various computers round the area had these and they intercommunicated via their 100baseT network. The reason for the limited spectrum radios is so that you could do a person to person communication or communicate to a specific group or combo of groups...

    Anyways...I ran across this at some ham radio site i happened upon, it was awesomely documented in text and pictures...I dont know for sure if they had an open design or not (but i vaguely remember they did), and I saw this about a year ago. i know this is kind of vague, but try poking around ham radio geek sites...somebodys always hooking something new up to a radio it seems...

  • More interesting than the ethernet intercom, I think: Are there ethernet based phones available?

    My opinions are mine.
  • by TheTomcat ( 53158 ) on Tuesday April 10, 2001 @01:21PM (#300600) Homepage
    why would someone use ethernet when radio-based (or, if you are careful...wire-based) communication products are cheaper and more robust?
    It needs to be controlable by a master computer that can link each user to any number of channels and change them around on the fly.

    isn't so easy to do with plain old radio..
    cool application, but likely VERY expensive..
  • is there anything off the shelf (and cheap) for this situation? i have my house wired with cat-5, and my mother-in-law lives downstairs. when both my wife and i are called to the hospital (we are both docs), i'd like to give her a quick message letting her know, so she can keep an eye on our 19 month old. i guess i could have a small computer in bedroom so that i can use ICQ/Netmeeting/etc. if the internet appliances drop in price, maybe those would work too, i guess.
  • maybe not TCP/IP, but he did mention some kind of server controlled switchable protocol, which conplicates things somewhat
  • by Controlio ( 78666 ) on Tuesday April 10, 2001 @01:23PM (#300603)
    Well - you're not gonna like the answer, but here it is. As clark625 has stated, ??-over-IP is NOT always the solution - and here is a perfect example. But what you want can be done with dedicated boxes.

    Clearcom makes wildly popular icom boxes. They have mainstations of all shapes and sizes - the more popular ones with either two or four isolated channels that can be "party-lined" together. The connector is XLR (3-wire mic cable), and each channel can support quite a few beltpacks at the same time. I also hear tell that they make wireless units, but I have no experience with these.

    Now - if you've got big bucks, you can get exactly what you want - an RTS Zeus DSP Intercom matrix. It is computer controlled, and allows for an unbelievable amount of private channels, grouping, external audio sources, etc etc etc. You can either get dumb stations (where their listen and talk sources and destinations are constant and pre-programmed), or you can buy the intelligent stations that have 12 programmable sources/destinations (not to mention you can have multiple pages and many other things). Each destination can be a party line, a private tunnel with an individual station, or an external source (like radio in our config). The stations are all 9-pin connections, and I can't tell you how wonderful this system is, if you have the money. They also make VERY reliable full duplex wireless units that I use daily.

    So those are the best bets for your situation - in this case, there's NO reason to reinvent the wheel. Use boxes that were MEANT to do the job properly, and don't overcomplicate things. Besides - I'm sure that in the middle of a production, the last thing you want is a script kiddie 0wn1ng your intercom system. Remember - there's no such thing as rm -rf / in the world of professional intercoms.
  • by Matt_Bennett ( 79107 ) on Tuesday April 10, 2001 @04:49PM (#300604) Homepage Journal
    Theres 2 intercom lines free for you.

    Using that extra pair can cause a serious drop in the performance of your Ethernet- the twisted pair/differential driver set up is pretty good at eliminating noise induced by outside sources, but only if the source of the noise is at a distance >> the spacing of the pairs. Since all 4 pairs are in the same shield, running intercom on the unused 2 pairs can interfere with the data (and vice versa). Also- you have to watch out since most Ethernet cards terminate the unused pairs into a direct short or into a 75 ohm resistor. Depending on how often you use it, it may still be acceptable, but you need to be aware that it can affect things.

    Also, using the extra pairs will prevent you from running copper-gigabit ethernet, which uses all 4 pairs.
  • There are lots of voice over packet office phone systems out there. For example, Selsius (acquired by Cisco) has a Voice Over IP (H.323) system that may match your needs... []. Of course it's not going to be cheap, but they do work - used them at a previous job.

    The advantage of IP phones in an office intercom scenario is: cabling cost - all Cat5, no separate "key system" or phone wiring; all ethernet instead of separate punch-down blocks and junctions.

  • Yes, Symbol makes one. Speaks H.323 over 802.11. Call by E.164 or IP addr.
  • You're missing the point. He wanted software, on-the-fly reconfig to allow people to set up intercom closed user groups on-demand.

    That's something not easily done with any existing intercom software. If you disagree, post a link or contact info to somebody who does offer it.

    These generic "IP won't save the world" flames are pointless when the reply completely misses the point of wanting functionality for a very specific application. Functionality which doesn't exist in present off-the-shelf technology.

  • Well, hang on, if he is asking for an Ethernet intercom, so why are you going on about a CAT5 intercom? In fact, he seems to be after a solution using 802.11.

    The concensus seems to be that there is needless complexity in what he asks.

    Essentially, one normally runs data over IP over ethernet over CAT5 and that is the normal scenario.

    Occasionally for some reason (usually trying to save money by using excess capacity on your WAN) you want to run voice over IP over ethernet over CAT5 ; and occassionally (because you want mobile computers or have trouble running cables) you want to run data over IP over 802.11 over radio waves. You could combine the two and do (deep breath) voice over IP over 802.11 over radio waves.

    However, if all you want is a wireless intercom, then there are products designed to run navive voice over radio; and these will be cheaper and simpler hand have bigger feature sets.

    But they're not very geeky.
  • Actually, even though the article says nothing about using IP, the debunker brings up some points that would actually make IP a great choice -

    Using NAT and some individual 10.x.x.x networks would give you a great network of com stations that you could send stuff to individually or over a broadcast.

    Wow, the more I think about it the more ideas I come up with. Teams of multiplayer paintball style games with wireless headsets, different channels of streamed MP3 background music, selectable by the player.. intercoms are only the beginning.

  • Yes, this is how I also take it.

    As I recall Cisco makes a phone that works over ethernet. Maybe they also have a similar product that'll work as an intercom? Maybe this phone even will? I've never looked into it, I just remember them annoucing that they were going to make it. But you might want to check into that.
  • Just to answer a few questions that various people have brought up.

    1. Why not just use standard wire/radio based intercoms? Basically for the same reasons that Disney is using ethernet to distribute audio throughout their new Tokyo theme park. The location I'm looking at will already have Ethernet drops EVERYWHERE and wireless Ethernet as well. Parallel wiring some other system is a lot of extra work, and in a high electrical noise environment a digital system will be much cleaner. Radio systems don't (usually) allow everyone on a channel to talk at once. Most commercial wired systems don't allow computers to control how people are linked together on channels.

    2. Why not use Gamevoice or other PC programs? A couple of reasons, first, the games I'm running will probably not be windows based, and most of these systems are windows. Second, all the ones I've tried are pretty poor quality, and don't allow party-line style mixing. Third, they don't provide any way for another program to control what channels you get assigned to...etc.

    3. Wouldn't other systems be cheaper? It's doubtful that any other setup would be cheaper in this instance. The cost of pulling extra cable everywhere would most likely kill it right there. Just about everywhere an intercom might be needed, there's already a Ethernet drop or wireless coverage.

    4. Worried about script kiddies? Not really, the site will be a high profile target anyway, so it will need to be be pretty well protected. If I describe a bit more this may make more sense. The place I'm talking about will have a variety of "cockpits" that players play games from. These can be on-the-fly grouped into multiplayer games of any size, number of teams...etc. ie: you might have one 32 player game with two teams one moment, then have 4 eight player games with two teams each the next. All this is setup from a central control console, which needs to be able to setup the channels for the intercom at the same time. Also, if someone has trouble while playing and hits a "help" button, we want to be able to switch them to a private channel with one of the site's operators, then switch back on the fly. At various times you would want to switch an intercom into the house PA system as well to make announcements or let people listen to a game. Another reason for wanting to use Ethernet is that occasionally, we may want to route intercom traffic between two sites via the Internet, so if the system was already all digital, it would make this easier.

    When I first saw the CobraNet stuff Disney was using, it looked pretty cool, but I quickly found that their audio in/out boxes typically have in's and out's only in groups of 8 or 16. This if fine if you're running a theme park, but for smaller setups you need something that can drive a single speaker.

    Ideally, I'd like a little beltpack-like box you could plug headphones/ethernet into for intercoms, a similar box designed to drive a speaker (including a power amp) and a central PC to handle all the mixing/control. There will be a ton of bandwidth available in this place, so it would be perfectly fine to send uncompressed audio like CobraNet does

    As much as I'd hate to do it, I get the feeling I may have to build the thing myself...anyone got any good suggestions for a small, cheap, single board computer with audio in/out, 100Base T Ethernet and just enough CPU horsepower to keep up with sending/receiving uncompressed audio?

    Hope this helps clarify things

  • If this is for a gaming environment, use a little of the bandwith available in your arena and just run a simple voice chat program like M$ Netmeeting off of the PC's in the background. That is assuming that your running a WinXX shop for games with user bliss and you have ful duplex sound cards. Your FPS may drop, but not to much if you restrict the voice quality sampling rate. Besides I saw that M$ is now offering a multi-point Netmeeting host for W2k server now. They may have a demo or somthing.

    No lost IP numbers, only a few extra ports in use, and you only need to buy some stereo headsets with boom mics, or offer your users to bring in their own $800 headphones and plug in a $5 mic that most manufactures give away now days.

    Make you life easy and stop wasting money. If your running Linux, I'm sure there is something out there like Netmeeting for you, but I could be wrong.
  • I have seen some type of game gear from microsoft that allows chatter during games, i have never tested it to know if it works for your application. I have ran across them at Radio shack and walmart so im sure they arnt too obscure.

    On the other hand (you hopefully have less than 6 digits), Motrola might have a buisness package set of radios that can work better than you would ever dream. If you listen to police scanners enough you may hear of cops losing radios and contacting a dispatcher to go over to the radio console and killing a radio's ability to work with the rest of the group. Also, if you work with motrola, you wont have any trouble with the FCC or buying licenses since motrolla will be the one buying the license for the spectrum you are using.

    Another option from motrola is a cell phone which also operates as a radio. from what i understand the usage as a radio incuurs no charges. One of the little towns i once walked a parade in seemed to have these cells phones everywhere.. The firefighters, the Church staff (the parade got rained out and I directed my float to a large covering at a church before our float got drowned and really started floating away)

    Stare at a few HAM sites, you will be blown away at some of the technology that's around already (please place a napkin over your keyboard so you dont drool on it).

  • up above somebody mentioned using Clear-Com belt backs. they were close, but they use 3 pin XLR connectors, you should look int othe Clear-Com matrix system... it runs over CAT5, and you can call from station to station, station to groups, have party-lines... the matrix is controllable by one or several computers, and you can even patch in phone lines ;)... I only wish I had one... the main problem is cost... their fuckin expensive!
  • Cat-5 has 8 wires, How many do you need for speaker/Mic? 2!
    How many does Ethernet use 4?
    Theres 2 intercom lines free for you.
    I don't know if this was exactly what you wanted though ;-)
  • a nice little win32 app for doing what u want from any desktop machine is roger wilco it works like a charm
    Kenny Sabarese
    Left Ear Music
    AIM: kfs27 #windowmaker
  • First of all, it is very feasible. I work for a major telecom company on VoIP, and I've got an ethernet phone. I can unplug it, walk over to another building, find a spare ethernet port, plug it in and my calls will find me. Existing software could be adapted quite easily, and yesterday /. even posted an article about an open source softswitch [](which is what manages a VoIP network). The biggest problem you would run into is that while there are a lot of ethernet phones out there, I don't know of any that could be easily converted into belt packs. A small PDA with wireless internet and voice memo recording capabilities might be a good place to start hacking (but rather expensive).

    Okay, so it can be done. (although probably not that cheap yet) What benefits would you gain? The biggest benefit would be flexibility. You could assign groupings based on users instead of equipment. Using convential intercom systems (at least a couple of years ago when I still worked in TV) if you wanted to re-configure more than 2 or 4 channels (groups) you had to re-wire accordingly. Plus, simply selecting A, B, C, or D channel didn't provide any security since anyone could flip their headset to any channel. For example, with ethernet intercoms you could easily set up 6 games of 5 users or 2 games of 15 users with a couple of keystrokes, and keep different games from interfering from each other. The staff could listen in on any game, and could use wireless lan technology to be mobile. The same ethernet cables providing the intercom could also be used to share data between the players. So.... is it worth it? Don't know but it's certainly an intersting idea.
  • First of all, no matter what the marketing people tell you, doing everything over IP is not the best solution for every idea out there. You have to ask yourself what you stand to gain by using an IP-based implementation; and in this particular area that isn't much. Intercom systems typically need 4-18# wires run to each station, with is cheaper and just slightly smaller in diameter than CAT5. So you aren't saving wire.

    Next, we have to ask if you want to do something special with your intercom; i.e. broadcast it over the internet, have access to a particular station from work, etc. If that's the case, then most off the shelf units require a "master station" that includes ways to connect auxillary devices. This would include a computer. Heck, my intercom system is over ten years old and has this ability. Granted, I only play MP3s to all the intercom units, but getting sound into the server wouldn't be much more difficult.

    Lastly, why would you want to give an IP to a device that has only one function? There are multiple ports, protocols, etc. that makes each individual IP address very generic. Why waste an address for something this silly? Certainly there are better uses of resources. Granted, I'm sure you'd be behind a NAT firewall; but that then begs the question why you would be even considering an IP solution.

    IP solutions can't save the world, people. They barely make it tolerable.

You don't have to know how the computer works, just how to work the computer.