In addition to standard mode (which uses just one telephone line), the CapTel 840 can be used in 2-line mode, which requires two separate telephone lines. With 2-line CapTel, you can turn captions on or off at any point during the call. Callers can dial your phone number directly, instead of calling through the Captioning Service first, and you will still receive captions throughout the call. 2-Line CapTel also allows users to enjoy advanced phone features they may have purchased, such as Call Waiting, while still receiving captions.