Ethernet wire connection to wall mounted box

Hi @natnaelfisseha

Usually there's 4 pins in an RJ45 socket when used as a telephone handset socket and the telephone wires connect to pins 4 and 5 (the middle two pins) when viewed from the front of the socket i.e. pins count Left → Right 1→8 but 1 & 2 and 7 & 8 are missing

Assuming the holes leading to the pins (where the wires are in) number 1, 3, 5, 7 on the back row (closest to pins when viewed from the back as seen in your image) and 2, 4, 6, 8 in the front row then the telephone wires would connect to the red and green wires.

If the telephone service is connected you should hear dial tone if you plug a telephone into the socket.

.