The "unknown machine" sounds like dtmf tones + pulse tones. It's anyone's guess what the actual meaning of the numbers are, but the tone+pulse encoding suggests a super legacy, perhaps proprietary automated system that you'd call up to get the status of something - maybe factory machinery or a power plant, but really it's anyone's guess. Pulse dialing was still somewhat common until the mid 80s so this system is potentially upwards of 40 years old.