RS232 Relay
From Leo's Notes
This page was last edited on 2 June 2017, at 23:33.
There is this RS232 Relay with 'www.iorelay.com' printed on the PCB.
I believe the manual for it is this: https://s3.amazonaws.com/assets.controlanything.com/manuals/R2X.PDF
On linux, I tried to do this to no avail:
# printf \\$(printf '%03o' 254) > /dev/ttyS0 ; printf \\$(printf '%03o' 4) > /dev/ttyS0