Wolfgang Heisig asked, "Is the meaning of Q.R.S. still unknown today?"

Will Herzog wrote, "The story we got on a QRS company tour was that
when they started business they were housed in a shared space.  The
postman put their mail into a mail slot, amongst the alphabet of firms,
marked 'Q-R-S'".

The rather more persuasive detail of this story was that QRS started as
the Rolls division of the Clark empire and the Q,R,S hole of the letter
rack simply stood for "Rolls".

Dan Wilson, London