Is that the Possum system? If so, came across it about 45 years ago at a home for disabled folk in Putney. Fascinated to talk to a young lady, wheelchair bound since birth, who used it to turn the light of her room on and off, turn on the TV, change channels, call for assistance, etc., all by blowing in a tube somehow.
I thought it was marvelous the independence it gave her when she had no control, to any useful degree, over her limbs.
I was accompanied by the matron as I toured the home and when we were alone, I did comment to her that the wrought iron motif over the gates read 'Putney Home and Hospital for Incurables'. Wasn't that depressing for the patients, I asked. Treated to a smile.
'The people in here can't see it, never mind read it. It's there to make people like you feel guilty about your good health.'
It worked - I was there because they had asked for monies from a budget for which I was responsible - found them £100k - worth about £580k in today's money
Mike