**Equipment & OS**:

 - Apple TV 2
 - Mac Pro (circa 2013 - the cylinder) 
 - MacOS Sierra Version 10.12.6
 - DAC (digital to analog converter, this only has USB and TOSLINK connections)
 - HDMI cable connects Mac Pro & Apple TV
 - TOSLINK (digital optical) cable connects Apple TV to DAC

**What I want to do...**

I want to use the Apple TV to stream iTunes music from my MacPro to the DAC which then connects directly to powered speakers.

Previously I have connected an earlier Mac Pro (circa 2009) directly to the DAC via TOSLINK.  This worked GREAT!  The earlier Mac Pro had a TOSLINK output.  The new Mac Pro (2013) doesn't.

Prior to that I has streamed iTunes wirelessly to the Apple TV which in turn connected by TOSLINK to the DAC.  This worked GREAT too!  When I set up this solution I had a TV monitor available that connected by HDMI to the Apple TV.

Unfortunately, I have no other monitor or TV display available to connect to the Apple TV.

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**Problems**

***<< System Preferences >> << Sound >>***

If I go to << System Preferences >> << Sound >> and look to "**Select a device for sound output**" I don't see the Apple TV connection via the HDMI.  Note, the Apple TV via the HDMI doesn't show up as an input either.

I do see the Apple TV available for AirPlay, but when I select it a pop-up window appears asking me to: "**Enter the AirPlay code for "Apple TV**"

I assume the "AirPlay code" is not a "password" for the Apple TV (my Apple ID password doesn't work).  I think the pop-up window wants one of those 4 to 6 digit "codes" that pops up on the device to which one wants to connect.   

As I don't have a monitor connected to the Apple TV I don't have anything that can display the "AirPlay code". 

Seems like the HDMI connection to the Apple TV should get me something, but I can't think of a way to make the Apple TV display appear on the monitors connected to the Mac Pro;-(

Suggestions appreciated.

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***iTunes***

I have similar problems in iTunes.  If I open iTunes and try to select an output device, I can select the Apple TV but the same pop-up window requesting the "AirPlay code" that I don't have a way to see appears.

Note: I have a 27" Apple Cinema Display, but it has not way to connect directly to the Apple TV.

Again, any suggestions much appreciated.

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Footnote -- If I had a shorter distance between the Mac Pro & the DAC I could use USB, but USB doesn't do well at distances beyond 20 feet.