Visiting Memories From The Past: Adtran HTU

Before I got into IT, I used to be an electronics technician.  I see these Adtran units all the time in provider smartjacks, but I saw this one sitting out and I visited my memories for a few minutes.  I used to troubleshoot these HTU units (on 3rd shift) down to component level back when I used to work for a company called Adtran, before I even knew what these things were.  That was a long time ago.
Take a look in your DMARC smartjack and you will see probably several of these inside.