Talkback with Broadcast G2s, ATEM 2 M/E & Clear-Com

We just added to URSA Broadcast G2s with SMPTE fiber converters to our ATEM 2 M/E Studio 4K remote production system. One of the big selling points of the G2s was that they would allow us to use our Clear-Com hardware. The first generation BDM fiber converters we used with our older cameras did not. So far, after many hours of cable building (thanks to the excellent support at Clear-Com) and fiddling around with our system after confirming the cables work, we can only, at best, hear the base station from the camera but nothing else. Talkback over SDI is enabled on the ATEM and the fiber converters are set to use SDI/DB25 and not tally.

When the camera headset was totally dead, I figured out that I need to connect the Clear-Com system to the ATEM chassis talkback. I built DB25 cables to pull the mic and earphone I/O (pins 14, 15, 17, 18) to plunge into a Clear-Com IF-4B 4-Wire Interface, which is connected to the base unit.

So here are some questions:

- Does the ATEM talkback I/O act like an intercom belt pack?
- Am I right in assuming it does not have power?
- Should I just be able to plug the ATEM talkback into the Clear-Com and have it handle both camera's comms?
- Why is talkback setup so minimally documented by BMD?

For the record, I called BMD support and the tech(?) I spoke to spent considerable time telling me why he doesn't handle "workflow" questions like this and how to use Google to search of answers on the BMD forum. He didn't say anything about the G2s needing to be physically linked to the ATEM talkback I/O, leaving to me to wonder what else am I missing.

I would be grateful if @Gary Adams would chime in on this.

Thanks,
Ric

1 BMD talkback is not very good.. if you are used to Clearcom or other intercoms.. But yes it will work in basic.

2 When you connect it to the DB25 on the basestations. The audio of embedded intercom from the Atem is ended.

3 To have talkback you need at least send a PGM return on RET1 else it wont work!!

4 Your fiber converters really need 1 of the latest firmwares..

5. Talkback IO in not an intercom beltpack.. It is line level in and out. Pluging the 2W from a Clearcom will instantly blow it up and its gone for good. ( So always need a 4W interface in between)

6 Test your setup on the 4W side with a simple powered speaker or into a sound board.. To check if you have levels coming out.

7 Badly documented as BMD intercom is a system on its own, meant to use only with there own gear. Yes they did make the 4W in out.. But that is indeed only to support some kind of external system. Unfortunately no levels can be set nor can you see if any signal is coming into the external Intercom IO..

[Gary Adams]

Hello Ric. Daniel is a great resource for these types of setups as he has loads of experience. I would like to offer additional help if you like. Feel free to PM me with your questions. In brief, with what you have there are a couple of methods to interface the Clear Com. None of them are belt pack style. We only provide a 4 Wire interface which will only connect to a 4 Wire interface. Clear Com and others have several of them. A 4 Wire interface is basic balanced analog audio at +0 or +4 levels in our case. They are not microphone levels. You can connect a 4 Wire interface to the ATEM which will distribute to all of the cameras. The better method is to connect a 4 Wire interface to each camera at the Studio Fiber Converter DB-25. This will give you complete control of the intercom to each camera rather than having them all share the same line. PM me if you have further questions. Hope this helps.

Regards, Gary

Daniel, Gary,

I too am connecting to a 3rd party intercom (Telos Infinity). Just to be clear - I need to connect the output of the Infinity to each (daisy chain) of our 4 URSA G2 studio fiber devices via the DB25?

Thanks

[Gary Adams]

Hello Rich. I don't have any experience with your intercom but a quick look at their website, it looks like you would need an analog Xnode for each camera. Wire the +4 balanced analog in and out appropriately to each Studio Fiber Converter at the DB-25. We use a +0 level so it would need to be adjusted slightly. I think that would put each camera on it's own with your system. You could possibly weigh the cost and give each camera a belt pack which would provide more functionality with your system. I hope this helps.

Regards, Gary

Gary,
I am not sure I am fully tracking this discussion. We too plan on utilizing our existing Clear-Com system. We were assuming that we could insert comms into the ATEM 2M/E 4K and then the communications would be carried in the SDI data stream???

We are in the process of building out a multi-cam BM system and we need some pre-sale support to make sure we are spec'ing all of the equipment we will need. I think the first question I have is if there is a path to speak with a BM system engineer to help us sort out our shopping list?

We have been searching the BM documentation but feel like we can't find all of the pertinent info. Please help!

Thank you,

Connecting URSA Broadcast G2 Fiber camera/Fiber Converter to analog Clear-Com


As it turns out, with the help of some great support by Blackmagic and Clear-Com, I was able to figure this out and get it working. To possibly save them a few calls in the future to make up for the time they gave me, I decided to write this up for anyone else who may need it.

Note that this solution may require some good soldering skills (especially if you need to build a headset 4 to 5-pin converter to use belt-pack headsets with your camera).

Overview & theory
Clear-Com analog base stations use two-wire technology where both directions of the talkback communications can be handled over two wires (bidirectional). Blackmagic (URSA cameras and ATEM switchers) use 4-wire; transmit (XMIT) and receive (RCV) are on different wires via balanced analog audio.

This requires the use of a 4 to 2-wire encoder. We used a Clear-Com IF-4B, their older model. The current version is the IF4W4 (~$1,600), which works pretty much the same. I’ll provide explanations of the settings I used so it can be translated to other products. These devices can support up to four inputs, which can be grouped together (via a party line setup) to feed the base station.

ATEM switchers carry intercom/talkback, camera talley and remote control via 4K (not HD!!) SDI program video. Connect Return 1 In on the fiber converter to 4K Program Out on the ATEM or an appropriate 4K distribution amp that is connected to Program Out. According to Blackmagic, a 6G Mini Converter will work for a 29.97 signal and a 12G for 59.94 frame rate.

On the back of the Blackmagic Fiber Camera Converter is a 25-pin DB25 connector that carries all the audio for communication (0dBu balanced) to and from the camera. We are using only one channel per camera (Production). It is possible to include a lot more, including a separate engineering channel, and two sets of tally lights separate from the ATEM.

Each audio communication channel requires two wires, XMIT (T) and RCV (R). On the Clear-Com side, the position of the + and - signals on the pairs are not an issue. There is no need for a third (ground) wire.

Building the Cable
You will need a DB25 (male) connector, either solder or screw-in type. I bought the screw-in kind, but for just four wires, I think it may not have saved much time. The guillotine-style terminals mean that the ends of the wires should be tinned or else the terminal style will be true to its name. Also, if you back off the screw too much, it can be a major pain to get back together.

There is a helpful table of all the DB25 pin-outs (“Talkback Pinout Diagram”) in the Fiber Converter section of the user manual. (Note that Blackmagic revises its documentation all the time, so referring to page numbers in these forums is essentially useless. The phrases in quotation marks should get you to the right place.)

Connect one pair of wires to pins 14 and 15. This is the communication signal that goes back to the camera. From the camera’s perspective it is considered RCV, that means it needs to be connected to the XMIT terminals on the Clear-Com. (This is super-important and I found it easy to screw up.)

The cables need to be long enough to go from the Studio Fiber Converter to the Clear-Com encoder. Because the signal is balanced, that can be a fair distance. As usual, label the cables clearly and test them for continuity and shorts.

On the Clear-Com side, I recommend either spade lugs (for the IF4B) or tinned ends for the newer model.

Settings and setup

Cabling:

• Connect the DB25 end of the cable you just built to the Fiber Converter
• Connect the separate wires to the IF4B (XMIT from the DB25 to RCV on the IF4B)

Studio Fiber Converter (Talkback):

• Input: SDI/DB25
• Start with mic and headset gain levels of 50%

Clear-Com IF4B:

• Set XMIT and RCV gain to about 50% to start
• DIP switch 1 & 2 UP to enable party line (all channels ganged together)
• DIP switch 5 DOWN; DIP switch 6 UP

Building an XLR 4–pin to 5-pin adapter
If all you have available are belt-pack headsets (4-pin XLR female) you will need to build an adapter for the URSA (5-pin XLR female). If you’re used to making/repairing 3-pin XLR audio cables, you may find the 5-pin very tricky. (I did.) The pins and wire receptacles are much smaller than the 3 and 4-pin connectors and far closer together. It is especially important to test this adapter for shorts as well as continuity.

I found using a cable length of 10-12 inches will make the build go more smoothly. There is a “Headset XLR Pinout Diagram” pin-out diagram.

I would also recommend building one spare adapter.



(Please DM me with any errors or suggestions for clarification)

Just a couple of notes to go along with the solution provided above..

You can use the Hollyland 2 to 4 wire converter for only $500 here (but this would need XLR ends, not just bare wire as mentioned above): https://www.bhphotovideo.com/c/product/ ... r_for.html

You can buy comms adapter cables here (in case you cant solder): http://jimirayo.pairserver.com/

You can have custom DB25 cables (and many other things) built here: https://customcableconnection.com/

Good information here.
Currently trouble shooting the following set up.

ClearCom HelixNet main to LQ remote over fiber.
The LQ has 8x 4W ports on the outputs.
built 4W to rj-45 per BMD maual.
I can test CC in and out on a Q box and is as it should.
When testing the BMD side, audio out from Constellation 2 M/E is garbled.
When injecting tone into the Constellation, nobody hears anything (cams or switcher).
I have some play in levels on the CC side and the ability to switch which audio pair is in or out (panel/matrix)
We had used it 2 weeks ago at a show and iafter lots of fiddling around got it to work ok-ish.
It is no longer functioning as it was, now just 1 way garbled voice.

I leaning toward failure in the Switcher.
We have 2 other systems that are impacted by the same dilemna ..anothet constellation and a 4k studio 2 M/E.

"tech support " says its warranty claim, but our festival starts in 3 days.

all cables have been tested and swapped around
Dynamic headsets were tested in various positions....
menues have been gone through ad nauseum

have plan b availble but would like this to work.

[Gary Adams]

Hello Walt. I tried to send you a PM but it's not going through. Send me one and maybe I can help.

Regards, Gary

Hey Ric,

Wondering if you can help me out. I am in the process of putting together the following.

ATEM Television Studio HD8
ATEM Camera Control panel
3 URSA Broadcast G2 Cameras w/ Camera Fiber Converters
3 Studio Fiber Converters.

I am trying to get third party, Clear-Com, intercom in to the studio fiber converters. In your earlier poast you mentioned that I need 4K program out from the ATEM to get the intercom feed to come down the SDI line out of the ATEM. As I listed above I am looking to use the Studio HD8, which I don't believe has 4K Program out. I am wanting to run 59.97 frame rate. The Clear-Com I am looking to connect into the system is a BS-702 3 wire system. Wondering if I can just run the 3 wire Claer-Com into your suggested IF-4B and then run that into the D-Sub 25 pin connector with XLR connections into the Studio Fiber converter? Just wondering if I absolutely need to go through the switcher for this to work.

Please let me know, thanks.

Peace, Pete

[Gary Adams]

Hello Pete. The SDI return from the ATEM to the Studio Fiber Converter needs to be the same frame rate as the camera frame rate. It doesn't need to match the resolution, although in most cases it will. That is all you need to support camera control, tally and talkback. For your external Talkback, connect the 4 Wire interface from your Clearcom unit to each of the Studio Fiber Converters according to the wiring pinout. I hope this helps.

Gary

Thanks Gary, that is helpful.

Peace, Pete

Ric, thank you for the detailed overview of your setup, it's incredibly helpful. I am in the process of installing a nearly identical system and wanted to ask a couple questions to clarify.

First, here's the equipment I'm working with:
- Blackmagic Design ATEM 2 M/E Production Studio 4K
- Analog Clear-Com intercom system, using a Clear-Com MS-704 and some beltpacks
- (4) Blackmagic URSA Broadcast G2s, equipped with the SMPTE Camera Fiber Converter
- (4) Blackmagic Studio Fiber Converters
- Studio Technologies Model 45A 2-wire to 4-wire interface

Notes about the system design:
- Everything is running in 3G Level A 1080p/59.94
- ATEM Program Out 2 is wired to a BMD SDI Distribution 4K, then to Return 1 input on each of the Studio Fiber Converters for camera control and tally (this part works).
- Clear-Com Channel A is wired to the 2W side of the Model 45A, and the 4W side then goes to the ATEM 4W in/out.

Questions regarding intercom:
It looks like the common approach here is to wire 4W intercom directly to the DB25 on each of the Studio Fiber Converters to achieve the best intercom results, instead of going through the ATEM. What advantages does that provides versus interfacing using a 2W/4W interface to connect directly to the ATEM, and let the ATEM handle intercom to the cameras? Is there more control over intercom levels and sidetone? Based on Blackmagic's documentation it would seem like this is the much easier approach, but I've already started to notice some odd behavior when plugging things in this way.

Do the intercom level adjustments on the Studio Fiber Converter only affect the DB25 connection and there's no way to adjust if using the audio from SDI ch. 15/16 embedded from the ATEM? Am I able to use the one Model 45A with 4 cameras, or would I need several of them? Davis mentioned using a Hollyland interface which is very similar to the Model 45A and only has one 4W in/out connection, so would I need 4 of those, one for each Studio Fiber Converter?

Thanks,
Mark