# VoIP technician communications



## cbenjes (Oct 7, 2009)

We are looking for an intercom solution using VoIP in our H.S's theater. We currently have a ETCnet TCP/IP network that controls the theater's lighting system. It's your typical physical star network consisting of a fast ethernet switch located backstage connecting RJ-45 outlets in our lighting control booth, catwalks and other backstage areas. In typical ETCnet fashion, the lighting board uses the network to communicate with the dimmer modules to operate the lighting fixtures throughout the theater. Very basic stuff....

We need some sort of voice communication between backstage, the booth and the catwalks. Sure, we could go with an expensive wireless setup consisting of transmitters and beltpacks, or we could save some money and install a wired system specifically for intercom purposes, but it seems to me that the technology should exist where we can plug a device into the existing TCP network and have seamless voice communications.

Is there a solution that would utilize VoIP through an existing network allowing technicians to communicate through headsets that connect to the theater's TCP/IP network?

I envision the product one of two ways:

1. An interface that plugs into the network through a switch or a hub, is configured with a network address, and then a headset can plug into this device and communicate with other headsets that are connected to other interfaces on the net.

2. A self-contained intelligent headset that connects directly to the network via RJ-45 and is itself a network node, complete with an IP address that talks to other intelligent headsets on the same network.

Such a system would not only be great for a theater, but any place where users have TCP/IP networks and require collaboration and voice communication. Have you seen/heard of anything?


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## sk8rsdad (Oct 7, 2009)

I think you are going to have difficulty finding a system that supports an n-way conference call, where 'n' is a number larger than 3 representing the maximum people able to be linked in simultaneously to a call. I am pretty sure your stage manager will not want to have to dial an extension to call a cue.

Assuming you are successful in finding such a system the next challenge is finding one that handles dropped calls gracefully. Most cheap cordless phone systems aren't designed for 4 hours of continuous talk time. We used to use a phone bridge to add wireless to our ClearCom and had to deal with dropped calls and the occasional howling headset.

There are a number of vendors making IP-DECT sets and base stations. The Mitel 1000 supports 4 wired and 4 DECT stations. I don't know much about it but I would be surprised if it supports an 8-way conference call. Maybe another vendor fills that niche, but I doubt it.

I also have a niggling sense of trepidation about introducing packet prioritization into your lighting network.

Happy hunting.


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## dvsDave (Oct 7, 2009)

I'm with sk8rsdad, I would be very, very hesitant about putting traffic that would need QoS enabled on the router.

At my day job, where I am the IT manager, over the past 8 months, we've been evaluating and getting quotes for a VoIP system to replace our aging digital system. As someone who's been in the market for such a system, I can tell you that VoIP does place a significant load on the network. 

Most of the systems we were looking at (SMB to entry level enterprise) didn't support conference calls to more than 8 people. I didn't ever see headsets that just jacked into the network and just "worked". The closest to this I saw was adding an $800 very, very high powered wifi access point and use wireless handsets (at $400 per handset, and that's before you buy a compatible headset) 

It's just not a feasible solution with today's current technology prices. It will actually be cheaper to buy a purpose-built headphone system than to build out a VoIP network that will do what you want. 

Also, the ETCNET is a dedicated network that is meant for ETC traffic. Shoehorning in traffic on a system that wasn't designed for that kind of traffic will always lead to issues.


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## derekleffew (Oct 7, 2009)

See also the thread Wireless Intercom/Skype.


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## icewolf08 (Oct 7, 2009)

The other problem is that, as has been mentioned, VoIP requires a lot of bandwidth, and that amount grows with every user. In general you don't want to run any unnecessary traffic on the same network as your show critical systems (lighting, in this case). All you need is a couple bad packets to really mess up your system.

All things considered, in the end you would probably spend the same amount of money on a wired coms system (Clear-Com, Telex, etc.) as you would to deploy a VoIP system that could do what you needed it to do. Going with a tried and true, proven technology is much better in a show critical environment.


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## fredthe (Oct 7, 2009)

ClearCom actually makes some VoIP products, but they are mainly intended for connecting to their high-end digital matrix system.

Note that VoIP can just refer to carrying voice data, signalling (such as for phone systems) is not necessarily required. Also, unless you're only running a 10Base-T network, I'd expect you can safely mix voice and lighting.

-Fred


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## TheDonkey (Oct 7, 2009)

Would it be feasibly possible for a company to develop some form of Teamspeak or Ventrillo-compatible beltpack?

TS and Vent are designed for Gamers, so you can have 64 people tunes into the same server. And the server can be split up into channels, allowing nay user to move back and forth as needed.

I'm not sure exactly about the mass-bandwidth requirments that it WOULD take to run a ~20 person(high estiamte) TS server, but the software's designed to run ove rthe internet and it does that well, so it can't be too bad. Especially if you have a 100base-T network.

The problem here is that TS is a Windows/Linux/Mac software, so you'd need to get a computer at every station.....But if seme company were to make a portable beltpack that can plug into the network....


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## epimetheus (Oct 8, 2009)

As others have said, do you really think it's a good idea to put other traffic on your lighting network? If you were to do something like this, I'd want to set it up such that you could prioritize the ETCnet above all other traffic, including VOIP. I'm curious about this myself and am in the process of setting up a home network lab to start playing around with this, and other network traffic in general.


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## NickJones (Oct 9, 2009)

What about setting up a phone system? I'm not sure how hard it would be to set up some form of conference calling but you said it was for communication between the stage, booth and cats, presumabley this is no replacement for a coms system, but if its just to call up to get a channel flashed it would be great. Get the phones that flash when a call is incoming, most have the ability to plug in a headset, and make sure it can be muted so as not to have loud ringing mid-show.
Just another idea.
Nick


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## renegadeblack (Oct 18, 2009)

Something that I recently used for a show was just your simple two-way business radio, I believe AVKid knows a bit about those. I forget exactly how it works, but it's possible to but Tx and Rx on two different frequencies so that it becomes a party line. Being in a high school setting, it also makes it easier to find out where everyone is during intermission and such as well as when you have your LED houselights start ghosting so you can quickly run to your dimmer rack and still be in touch with whoever is in the booth.


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