Pin D2 is HIGH, pin D3 is LOW and pin D4 is HIGH.
A short call with back light on for under 20 seconds will turn on the socket for 30 minutes. If you decide that you want to cancel, a short number of rings that keeps the back light on less than 20 seconds will turn the socket OFF.
See Mode 1 for explanation of backlight timings.
This Mode is ideal for turning ON the socket with an automated text. See below on AUTOMATIC OPERATION OF SOCKETS.