Hi all,

I know this thread seems to never die, but I thought I'd just share in case someone else could benefit, the commands for working with the Bose LS 50 unit are as follows via a TTL 5v Serial connection with Baud 4800,1,n,8

Command -> Function
MM 4a,41,01 -> Power On
MM 4a,43,01 -> Power Off
MM 42,40,01,02 -> Room A Source CD
MM 42,40,02,02 -> Room B Source CD
MM 42,40,04,02 -> Room C Source CD
MM 42,40,08,02 -> Room D Source CD
MM 42,40,01,01 -> Room A Source FM
MM 42,40,02,01 -> Room B Source FM
MM 42,40,04,01 -> Room C Source FM
MM 42,40,08,01 -> Room D Source FM
MM 42,40,01,03 -> Room A Source Aux
MM 42,40,02,03 -> Room B Source Aux
MM 42,40,04,03 -> Room C Source Aux
MM 42,40,08,03 -> Room D Source Aux
MM 42,40,01,04 -> Room A Source Video 1
MM 42,40,02,04 -> Room B Source Video 1
MM 42,40,04,04 -> Room C Source Video 1
MM 42,40,08,04 -> Room D Source Video 1
MM 42,40,01,05 -> Room A Source Video 2
MM 42,40,02,05 -> Room B Source Video 2
MM 42,40,04,05 -> Room C Source Video 2
MM 42,40,08,05 -> Room D Source Video 2
MM 42,40,01,06 -> Room A Source Tape
MM 42,40,02,06 -> Room B Source Tape
MM 42,40,04,06 -> Room C Source Tape
MM 42,40,08,06 -> Room D Source Tape
MM 44,41,00 -> Room A Vol +
MM 44,42,00 -> Room A Vol -
MM 43,41,01 -> Room A Mute
MM 43,40,01 -> Room A Unmute
MM 44,41,01 -> Room B Vol +
MM 44,42,01 -> Room B Vol -
MM 43,41,02 -> Room B Mute
MM 43,40,02 -> Room B Unmute
MM 44,41,02 -> RoomC Vol +
MM 44,42,02 -> RoomC Vol -
MM 43,41,04 -> RoomC Mute
MM 43,40,04 -> RoomC Unmute
MM 44,41,03 -> Room D Vol +
MM 44,42,03 -> Room D Vol -
MM 43,41,08 -> Room D Mute
MM 43,40,08 -> Room D Unmute

You can directly paste the command i.e: "MM 43,40,08" with a newline "\n" at the end and it will accept it.

I'm building a few python scripts to interface with Home Assistant and my Kodi running pyserial and connected to the Bose LS 50 via a TTL Serial adapter. I will share them once I've got it all working well.