Sony VGC-RC300 - Manual (Page 23)

23 n N
Getting Started
To connect the telephone and modem
1 Unplug the phone cable to your telephone from the wall jack.
2 Plug it into one of the ports on a "1-to-2" port adapter device (splitter) (1).
3 Plug one end of a second phone cable (not supplied) into the other port on the splitter device.
4 Insert the plug end of the splitter device into the wall jack.
5 Plug the other end of the second phone cable (2) into the modem port (3) on the back of the computer.