Apple TV 1st or second generation not in devices list

Question

After upgrading to Yosemite and reading a lot  about how  to RE connect my Apple TV to my home network even though I kept getting false message of being successful.
Finally I took an Airport Express I use on a speaker system and plugged it in the Apple TV  I was able to get a complete address for the connection.
By mistake I wiped off the synced movies and photos and what ever I had working just fine except ATV not showing in my I tunes to further sync.
I opened the port and tried a dozen other things and finally Airplay played my music on the TV speakers,  but no data on my ATV.
This is a fine piece of expensive storage and up until now it has been a treasure in my household.
To make a long story shorter  I took the ATV and plugged it in the power  and connected it to my I MAC with a DSL cable.  It is Syncing.
At least it will get my data  onto this  HAS BEEN Great unit.
I spent so much time  just trying to enter the pairing number the ATV gave to enter on the Device section.  Of course this is what needs to be fixed
by Apple.   For heavens sake!  ADD BACK THE ATV TO THE DEVICE SECTION so it can be directed to SYNC!!!!!!!!!
This is not yahoo or google or microsoft TV  IT's  APPLE  TV!!!!!!!!!!!!!!
I am connecting to the Internet through an AT&T modem and a Time Capsule.  Even the AT&T unit recognized my ATV to give it permission
to the port settings.  Why on earth would my Fabulous I MAC play dumb and not recognize it.
Please FIX the  problem. 
Thank you,
Elisabeth
"You are not allowed to create or update this content"
This is the message you gave me    DO YOU REALLY CARE ABOUT THIS PROBLEM????????????

Answer 1

Hi Winston,
Working with 1st Generation ATV A1218 Model.  I MACUpgraded from Snow Leopard to Yosemite 10.10.1.
Before the update automatic Sync was seamlessly working. I had I photos, Music and Movies on the ATV.  I wish I did not clear all data inadvertently
in my un successful attempts to wirelessly re connect to my home network. I figured things would find their bearings as all the Apple equipment always has in my past experience. Apple care has graciously helped out when I got stuck.  Even in this case an apple Rep. suggested to plug in the  Airport Express to get the proper connection address.  I happily told him,  I can figure out the rest.  Well;  maybe not so fast.
I am not sure where I stand on what is on my ATV after the direct DSL method connection to SYNC from my I MAC  since we have not turned on ATV since that event.  We listen to all the News Interviews Sunday mornings.
I did try a test on the DSL cable Music sync by creating a play list of smooth jazz in order of artists.  After the sync finished on the DSL cable connect,
I decided to change the Jazz  to the title of the songs  by creating a new play list and deleting the one with artist order. I asked the RE sync and the darn thing pretended doing it  but the information stayed the old artist order.
As you can see this is a work in progress and will keep you posted on the progress.  Thank you for your response.  Happy New Year.
Elisabeth
The bottom line is,  I am able to play music from my computer to ATV  probably through AirTunes  which is just fine to three different speakers at the same time,  but I liked to see all my lovely pictures  while music played and I really don't want all the movies I have purchased clogging up my IMAC and while my future purchases will very likely be housed on ATV  I kind of like the way it worked seamlessly before.
At this point  I just wonder  if not being able to enter a PAIRING NUMBER on my IMAc is really the stumbling block of the SYNC deficiency.
Hope this is not too confusing.