If you have cordless phones, please sound off here

I had what might be a fabulous idea.  I have been trying to come up with a brilliant plan to put clearcoms in my theater.  For those of you who don't know, Clearcom is the headset system you see on tech folks, camera operators, etc.  It is much like a phone where you can TX and RX simultaneously.  Problem is, I have next to no budget and a good wireless clearcom system will cost about $10,000.

So I had the idea to use cordless phones.  Just get a system with about 4 handsets and some earbuds.  We all press talk and we would have comm with each other.  The problem I am having is that most of the newer cordless phones are too "smart."  If they don't have a dial tone they just beep and shut off, or they have specific ability to talk to one other handset at a time.  I remember our first cordless phone I could page the other handset and dad would hit talk in the garage and we could communicate... albeit with a dial tone, but if you unplugged the cord the dial tone went away and we could still talk.

So, if you have cordless phones in your house that would let multiple handsets be "off the hook" and talk to each other through the base, let me know a brand and model that might work for this crazy idea.

There are some out there with an "intercom" option.  That would probably work for you.  BTW, I'm looking for some myself.  Haven't pulled the trigger yet, but I'm looking.

Usually the ones with intercom (at least that I've seen) let you choose which handset, but not let you choose all.

I was hoping for a dumb one that just let you press talk on all of them kind of use it like an old-school corded phone.

We still have a landline in the house because of moms hearing aids. I haven't seen a cordless phone like you're after since the late 90s. I'm sure they might still be out there, but I don't know where.  maybe goodwills or ebay?

Would a $50 set of walkie talkies help? But I feel like we talked about doing that at your theater before and there was an interference issue

They would work in a pinch.  One of the real benefits to a party line setup is that you can interrupt.  Someone is calling a cue and someone else notices a curtain flying in is going to hit an actor... with a talkie you can't interrupt to prevent death.  Not a huge issue for us here at the blackbox, but it is a nice feature.

My wireless DMX is 2.4ghz and doesn't seem to mess with the wifi or vice versa.  FRS is in the low 460mhz, so no worries there.  The real problem with FRS is that I'm not supposed to use it for "commercial" purposes, and it might be difficult to find an open channel that doesn't get interrupted by a kid trying to reach E.T. in the middle of a show.

Buying a dedicated frequency requires an FCC license which is money we don't have.... for the license or the radios.

Uh oh.... rabbit hole.

Tell me about Raspberry Pi and Mumble.  

Curtis said:

 Someone is calling a cue and someone else notices a curtain flying in is going to hit an actor... with a talkie you can't interrupt to prevent death.  

I know this isn't the exact trauma but he did get walloped at the Tonys and sued. 

I love that he's in a hospital bed with a brain injury, but still has his bandana on

Just bought a set from Best Buy. Panasonic model KX-TGD560. About $89 for the full set of 4. 

They work like you described. You can talk over the dial tone, and if you unplug the phone line, you can continue to talk. They also have intercom ability- you can page 1 specific phone or all of them. 

They do not have earbud output jacks. You could probably get creative with a soldering iron. 

They are also Bluetooth compatible. The system can be expanded to include up to 2 Bluetooth cell phones, or a headset. 

A silent page might be a little tricky. 

Is it possible a smart phone app would work? My work phone has https://zello.com and it turns a phone into a two way radio.

zello and other apps of that nature use a remote server and the lag is pretty intense.  Has to be real time.  You talk, it goes through the router, out to the intarwebs, bounces around, and comes back about 3 seconds later.

Svrex, thanks for the update.  Maybe they make a model with the jack.

I don't remember where it came from or what it was called but someone once loaned me a telephone diagnostic tool that emulated the phone company side of a telephone system.  You could use it to fake the system into thinking it had a live phone connection.  Something like that might allow you to use pretty much any cordless phone.

In reply to APEowner :

Don’t need a live line. 

If I disconnect the phone line from mine then pick them up, I can talk between units with no issues (and no dial tone)

In reply to Curtis :

There are probably ones with headphone jacks. 

The operator’s manual for mine shows many different model numbers (and that’s just Panasonic)

You can fool the “smart” ones into working without a phone line by using a telephone line emulator. I made one and used it with a modem to do local programming if my security system that only had phone line connections. Essentially what you’re doing is putting 24vac on the phone line and connecting them all together. Here’s a diagram:

I believe you could connect multiple phones to that. 

This is all such good info.  I have several great ideas from you guys.

I downloaded Mumble on my desktop to try it out and I think it might work, but I can't get it to work on the laptop in the tech booth because I don't seem to have Bonjour on that one  (this is all PC)

I think I'm going to try making that laptop the Mumble server hooked up to its own WAN router.  Then my other techies can connect to it with Mumble on their phone.  My only real investment would be some earbuds and a couple actual headsets for the booth.  That doesn't solve the tech-challenged volunteers, but I can scavenge up a couple old smart phones to have prepped for them.

I also have this brilliant idea for when we tour a show... I have a bluetooth adapter which I can hook up to the XLR in the host house to connect to the laptop and hopefully be able to configure it to connect my Mumble phones to the house clearcom.

If that proves to be too complex, maybe an old cordless phone setup with earbuds/headsets is the key.

You may want to look into Skype. I don’t know how much it would cost, but get everyone a Bluetooth headset, and have them all download Skype to their phone (or provide them with a phone to do this). I’ve had 4 hour meetings through Skype with people in 4 states, along with my boss and I from different phones 10 feet apart. Should be no reason that this doesn’t work, assuming that your WiFi in the building can handle it. 

Again, skype uses remote servers.  Major lag.  This has to be next to zero lag.  I have had multiple skype conferences where it's just dead space and then 5 people start talking at once and it takes a few seconds for them to realize that everyone is talking.  Then they all say, "go ahead" at the same time.

In my testing of Mumble, the server was my own computer, and the delay was incredibly short.  Maybe a couple milliseconds.

For multiple reasons, this must be internal only.  Not only for the lag reasons associated with remote servers, but also for the sake of privacy.  The other thing is, if the internet goes down, we're humped.  We don't pay for lightning fast internet.  It's a non-profit theater with only 5 on staff, so it's not like we need gigabit.  I think we're at about 20 down and 10 up.

For that reason I want an all-internal thing.  Either a cordless phone setup, or configure a VoIP server on a central computer and wifi it out on a hidden/secured router.

Following this out of curiosity.

I was going to suggest mumble or some other gaming service. 

I would suggest not running it on a Pi, or if you do, stress test it.  Pis are great, but in my experience they are like 99% reliable.  you don't want 1 in 100 of your shows to go to E36 M3 because you lose all communication in the middle of it.  Also I would put your Pi on some sort of power backup, or at a minimum once you have everything up and configured, back up the SD card.  If you remove power from a pi, it doesn't do a 'safe' shutdown and corrupts the SD card more and more each time.  Eventually it will all go to E36 M3.  Probably a good habit to power it down after each usage if you are not able to put it behind a UPS or something.

Definitely hardwire the Pi Ethernet at a minimum (and any others you can), for 2 reasons.  1) the Pi wifi is garbage slow.  2) wifi is silly unstable when compared to hardwired Ethernet.

All that said, I really have no idea who/what is using it in your situation.  People at a control panel?  People at a desk?  Can they see a screen or not?  Do they have their hands free?

In reply to ProDarwin :

Generally live theatre has stagehands that communicate during the show. Every show is different- stuff happens. 

When an actor drops a line, or starts saying lines from Act 3 when everyone else is still in Act 1, there is a lot of improvisation going on. The actors do things that are unpredictable, and the stagehands adapt. 

The stage manager gives directions and cues. They are talking to the lighting console operator, the sound engineer, follow spot operators, back stage scene techs, etc. 

Generally, a system is wireless battery powered headsets with mikes- no visual or computer screens. The lighting and sound techs may have access to a screen, but no one else. And everyone needs both their hands. 

Curtis is trying to come up with a work around. 

Curtis... the hands are gonna be a problem for several of the solutions you are considering. 

I also think that cell phone solutions are gonna create too many problems. For example... what happens when a stagehand’s screen lights up during a scene change, or someone forgets to turn off their ringer?  How do you keep a bored tech under a turntable waiting for his cue from playing on his phone?

Don't make some things too easy. (Like access to our own cell phone addictions)

ProDarwin said:

All that said, I really have no idea who/what is using it in your situation.  People at a control panel?  People at a desk?  Can they see a screen or not?  Do they have their hands free?

Like Svrex said...

The most common form of communication for tech backstage is Clearcom (which is a kleenex name along with Telex.... we usually refer to it as "on headset").  It is a party line/duplex open communication thing that typically operates from a standalone box and connected with XLR.  It's basically a dedicated, hard-wired phone that let's you talk in analog real-time.  The belt packs typically have a PTT button that if you double click it keeps your mic on.  We do two basic types of productions; in-house at our black box production center, and a "tour" which only ever goes one place, a proscenium theater downtown.  The downtown location has wired coms from Clearcom.  The basic idea is that it provides a 30v "phantom" carrier signal through a rack-mounted magic box that connects to a dedicated XLR node.  You plug in a belt pack to the XLR and plug a headset into the belt pack and you have comm with everyone else.  The problem is that you are tethered to an XLR cable.  They make wireless systems, but a 4-headset system starts at around $10k.

At the "tour" theater downtown, wired is fine once the show starts.  Everyone backstage is in their spot and any movement they make is within the 25' XLR cable range.  I like to be in the lobby kissing hands and shaking babies.  It is a massive theater. Most of the time, I have the ability to turn the production over to a talented crew and I can go loiter in the lobby and have a beer with my patrons.  Since it is volunteer community theater with wee little stipends for key production members, there is always the occasional "my wife's having a baby" or "my car won't start" or "how do I turn on the lights" amateur hour BS and I need to be notified immediately, not once someone finds me among 700 people in a 40,000 sqft facility,   At our smaller black box theater, we all fill multiple roles.  it is a small space with a capacity for about 150 patrons.  Getting through the crowd to check box office ticket sales, find the stage manager to tell them to hold the curtain for 5 minutes, or have a stagehand inform me that the set is on fire is a daunting affair.  It's kinda like trying to find your friends at a dance club with 150 people who all seem to know YOU (but you've never seen them in your life) and want to discuss the nuances of symbolism in the play as you walk by on the way to the aforementioned inferno.   I need to be mobile and have easy communication with the rest of the tech crew, box office, concessions, ushers, etc.

It's like being a security guard for a band, but you need the ability for duplex, two-way communication during the performance.  Walkies don't cut the mustard.  You need the ability to interrupt.  650-lb set piece coming down from the fly rail straight toward an actor who missed their cue?  Yup.  It has to be an interruption.  If some non-tech-savvy volunteer sits down on their talkabout's PTT button, someone could die.  That is an outside exaggeration, but it's actually a real possibility.  Because of our lack of that type of comm ability, we have to tailor our set designs to the fact that we can't communicate in ways we need to.  We could do so much more if we had comm ability.

In a typical production at the small theater, I will have a stage manager calling cues.  ("light cue 46 and scene shift 21... GO...*30 seconds of silence*... standby scene shift 22, light cue 47 through 49, and sound cue 18"  you get the idea)

Based on all of that, avoid mumble or any software based solution that is going to run on compromised devices.  You not only have the Pi issue to deal with (or small PC), - which isn't that bad - you have a bunch of other smart devices to deal with.  Apps crash, phones crash, wifi drops out, etc. etc.  If you can dedicate one (theatre owned, locked down) device per person you can minimize this (perhaps POE Pi 3B+?). 

I'd be trying to build my own analog or harware-based digital system on the cheap.

The short answer is that we need com for a bunch of people.  Our next production needs 0 com, but could benefit from 2-3.  Our tour shows could need anywhere from 3 to 10, but we only have the capacity for 4.  Of that 10, only about 4 need the ability to talk, but we are crippled by hand signals and whispers.

Take a look at this video.  Starting at about 20 seconds, you get a glimpse into the life of what happens backstage at a theater.

Organized chaos!

Surely this is a common problem and others out there have been working on solutions for it.  Whats the expensive part of the analog setups?  Everything?

I recall you had a thread a while ago regarding running Cat6 all over the place with some patch panels in your theater... was this the reason?

I might give a dedicated client device using the pi/mumble route a go.  Might up your cost a bit, but even if you had a Pi at each location, it would still be cheap.  A quick googling shows people doing this with a headless setup on each one.