Interface the ATEM Camera Converter to an RTS System

[Chuck Pullen]

Thanks guys! I didn’t realize that the Camera Converter wasn’t full duplex, your explanations make the problem much clearer to me now. I think the SSA-324 would work well, and I hadn’t thought of using Studio Tech products. I’ve already had a discussion with Joseph Electronics about the possibility of a custom solution using Studio Tech and their cabling.

And Bob…Not everyone consults for “big companies” as you put it. My work is mostly for small churches and schools. In this particular installation, the church has a perfectly good and relatively new HD ready control room and a completely functional RTS system. Now I realize in your world it just makes more sense to completely gut the whole thing and start over with the latest greatest (expensive) product from NAB, but in MY world, all I need to do is add just 1 camera out of the 300’ range of SDI cable. Asking for just an extra $1000 to add the Blackmagic Camera Converter and fiber has been a long term discussion, as this church is very protective of “God’s Money” which is a very admirable thing for church leadership. Now I would really have a hard time sleeping at night if I was constantly talking my clients into spending thousands of dollars when thanks to the good guys here at the Cow I now have several less expensive solutions…My soap box and I will take our leave!

Chuck

[Richard Crowley]

The ATEM Camera Converter IS full duplex. I understand Mr. Zelin’s arguments, but don’t necessarily agree with his suggested reasons. BMD is operating from a new generation of technology than the traditional intercom systems. I would argue that it is TWO generations newer. With the kind of data bandwidth they have on those fibers, throwing in intercom functionality is almost free. It is just an additional few K bytes of data along with the gigabytes of video data.

The problem comes when you have to interface that digital intercom world to the old-school, legacy analog intercom systems. BMD appears to have a rather provincial view of the world that doesn’t uniformly comprehend that their equipment is only PART of a larger system comprising equipment from other vendors and using other technology and interfacing.

There is also the matter of the size of the market and what the market will bear. There is FAR more technology in a consumer $40 bluetooth headset than in the typical professional intercom station. But the economies of scale and the traditional price of professional equipment make an intercom system cost many times what a bluetooth headset sells for.

Now BMD (or perhaps a 3rd party vendor) could make a small interface box the size of the BMD Tally/GPI interface box that could interface with the common 2-wire systems like Clearcom, RTS, et.al. Consumer goods that have the level of technology required to do this cost less than $100.

You could make the argument (and my suggestion was based on the theory) that one of the ATEM Camera Converter boxes is actually the best available analog interface into the ATEM intercom system.

BMD’s products are an interesting mix of products that are amazing value for the price and others that seem dramatically overpriced by comparison.

[Jeff Hartman]

I was rather surprised to see such a snarky response to fairly straightforward replies. Yes, Blackmagic gear is low-budget… but RTS decidedly isn’t. For a facility that already has a full RTS system and wants to tie it into a new piece of BMD equipment, citing an RTS interface as a known-good solution is certainly not unreasonable.

Having said that, if low price is the only constraint, it’s quite straightforward to build a hybrid circuit with two transformers (two Triad TY-300P, for instance), one 560 ohm resistor, and one 100 ohm potentiometer. This will achieve a fairly decent null between the BMD incoming and outgoing audio (set the potentiometer to minimize the sidetone at the camera end). Total parts cost should be under $20 from Digikey.

If you take a look at the description of the double transformer hybrid on Wikipedia’s “Hybrid Coil” page, “W” would connect to the RTS coupling jack, “X” would be the BMD send audio (with an attenuator to drop it to mic level), “Z” would be the BMD receive audio, and “Y” would be the 560 ohm resistor in series with the 100 ohm potentiometer. The dots in the drawing indicate the polarity for each transformer winding, and it’s essential to observe correct polarity or else the hybrid won’t work correctly.

The downside is that this is a very rudimentary approach. Aside from needing some skill to build and some effort to tweak so it works decently, it lacks the automatic nulling, ducking, and dynamics control that you get with an RTS interface.

One other observation about intercoms in general: both two-wire and four-wire systems have been around for a very long time, and each has its advantages. The RTS TW system is two-wire; the digital RTS Adam is four-wire, and I happen to have installed both here. I see no significance in Blackmagic’s design approach beyond the fact that since their system transmits and receives separately, the link is intrinically four-wire; there is nothing to be gained and a lot to lose by adding four-wire to two-wire conversion if you don’t actually need it.

— Jeff

[Chuck Pullen]

[Jeff Hartman] “I was rather surprised to see such a snarky response to fairly straightforward replies”

Snarky replies are his specialty! LOL

Thank you for the detailed response I am certainly going to read up on the hybrid coil and see if it’s something I want to attempt. As mentioned we have a perfectly good RTS system that I am perfectly happy with and I have no intention of abandoning any time soon. I am surprised that Blackmagic hasn’t come out with a solution to what would appear to be an obvious problem. When I started using Eartec wireless intercom equipment the very first question I had was “How can I interface this with my RTS?” Guess what, they already solved the problem before I asked the question with this: https://eartec.com/SLTalk%20Interface/sltinterface.html

Maybe Blackmagic will stop being “elitist” and start making their products to play nice with others?

Chuck

[Jeff Hartman]

[Chuck Pullen] “Maybe Blackmagic will stop being “elitist” and start making their products to play nice with others?”

I’m not sure it’s fair to say they’re being elitist: from a purely technical point of view, a four-wire system can outperform a two-wire system in many respects, and it’s consistent with how the signals are transmitted over the fiber. Adding two-wire conversion would seriously degrade the performance when linking multiple units together, because there’s a practical limit to how much gain you can create in each direction without making the system unstable and breaking into feedback.

As far as interfacing goes… the BMD actually interconnects really well into a system like our RTS Adam, or our Telex wireless base stations. I’ve been installing and designing intercom systems for years, and the big problem for every single one is interfacing to a dissimilar system — especially when you have to tie into things like phone lines, camera base stations, wireless systems, and the like.

I suppose I should be grateful: at least it’s a perverse sort of job security. (grin)

— Jeff

[Bob Zelin]

Chuck writes –
Maybe Blackmagic will stop being “elitist” and start making their products to play nice with others?

Snarly Bob responds –

The headphone jack supports iPhone-compatible headsets, where the microphone works via the headphone
jack. If both an iPhone-compatible headset and external microphone are connected at the same time, the
iPhone microphone will mute and the external microphone will be used instead.

It appears that the real intention here is NOT to interface with the rest of the world (RTS, ClearCom, Eartec, Telex, Anchor, Studio-Tech, etc.) but to connect to the Blackmagic ATEM Studio Converter, to have a nice simple self contained talkback system. So you can go to Digikey and Jameco to jury rig up an interface, but it looks like Blackmagic’s intentions are for you to use multiple ATEM Camera Converters, and their self contained intercom system (who needs IFB anyway !).

So maybe in the same way that they now do ProRes and DNxHD to “play nice” with the post production market – maybe they will do the same for 2 wire systems.

Bob Zelin

[Chuck Pullen]

See Bob, you CAN be helpful!

At a certain point this will become a “take what I can get” project. If I find a simple way (Several good recommendations above) to tie this into the RTS system,problem solved. If I can’t get that to work, the yes this will become a one way communication system (Like any director wants to hear from the camera people anyway) Either way, this what my budget constrains me to work with…

I never thought I would see the day that we were discussing using iPhone and Bluetooth headsets for comm.. I miss my old heavy Telex headset already!

Chuck

[Shaun Roemich]

IPhone headsets…

THOSE will be AWESOME for camera operators in a room any louder than a church sanctuary… (Snarky Shaun joins in)

I have used FRS radios as a low cost solution for live event coverage for years when the budget wouldn’t support real comms. And guess what? Every time I do I swear “never again”! Not because of the radio transmission but because the headsets are AWFUL in terms of either amplitude or noise insulation so my camera guys actually have a hot clue what I’m asking for…

Wired comms with one ear headsets for my ENG style camera ops, option of one or two for my studio kit equipped ops and either for me, depending on whether I need to work with anyone in the room not on comms.

Big Dog – Technical Director – Switcher
Road Dog Media – Vancouver, BC Canada
roaddogmedia@gmail.com

[Scott Thomas]

I don’t know whether it would work… I thought a while back that if I had to do this, I would try the Eartec wired Intercom adaptor (~$215). Eartec makes it to go from a wired intercom (RTS, Clearcom, Telex, etc) to the headphone jack of one of their wireless beltpacks (which use a single 2.5mm or 3.5mm plug headset plug (I’m not sure which)). I would guess that with a breakout adapter cable it would probably plug into the ATEM Camera Converter/Studio Converter.

Adaptor:
https://eartec.com/SLTalk%20Interface/sltinterface.html

https://www.bhphotovideo.com/c/product/723694-REG/Eartec_SLT_INT_SLT_INT_Wireless_to_Wired.html

Adaptor Plug (3.5mm or 2.5mm)
https://www.amazon.com/GTMax-Headset-Adapter-Smartphone-Converts/dp/B0046FMRGA/ref=pd_cp_e_1

https://www.amazon.com/2-5mm-Mobile-Headset-To-Converter/dp/B000IZCUTQ

–Scott

[Jef Kethley]

We used the Production Intercom AD903 to interface our 2wire ClearCom system into the ATEM converter world. After a little tweaking time, all works fantastic.

You can also use this same box to interface ClearCom 2Wire to RTS 4Wire. Not bad for a $300 ish box.