"CJT" wrote in message
Two months ago I had a new wall unit a/c installed with a remote
control. Now when
the a/c automatically turns on, the entertainment system goes on and
off.


??? The OP said when the A/C "automatically" comes on -- I took that to
mean without anybody touching the remote.



A little confusing as he wants to know if remotes talk to each other.
Could be that the AC is sending an IR beam when it turns on. I'd try taping
over the sensor on the AC to see what happens.
OTOH, it is late September and getting too cool