The below answer is assuming that you have enabled POST/GET with Username: admin & Password: Admin123
So the POST/GET URL is as below.
http://192.168.1.1/cgi-bin/io_state?username=admin&password=Admin123&pin=relay0&state=closed
The "relay0" can be replaced with the necessary parameters as given below for controlling other I/O pins.
din1 - 4PIN input
dout1 - 4PIN output
din2 - Digital input (only for passive sensors)
dout2 - Galvanically isolated open collector output
relay0 - Digital relay output
iio - Digital galvanically isolated input
adc0 - Analog input
acl0 - Analog Current loop
Hope this helps..!!
Regards
Clive Simon Victor Pinto