The T20 can be connected to 2 separate telephone lines.
1) Connect the AC power adapter to the T20. Plug the other end into a wall outlet.
2) Connect the T20 to the telephone line in your wall.
3) Set the Tone/Pulse switch (touch-tone phones can use tone).
4) Set the Ringer Volume Control for incoming calls to your preferred level.
5) Plug the headset into the T20's Headset Jack.
6) For most U.S. customers, the flash timing switch (for call waiting) should be set to "3. ” However, trying other settings will not harm the T20 or your phone line.
Please see the User's Guide below for more information.