Pin D2 is HIGH and pins D3 and D4 are LOW.
A short call with back light on for under 20 seconds will turn the socket ON for 60 seconds. If you decide that you want to cancel, a short number of rings that keeps the phone back light on for under 20 seconds will turn the socket OFF.
This Mode is ideal for turning ON the socket with an automated text
See Mode 1 for explanation of backlight timings.
See AUTOMATIC OPERATION OF SOCKETS.