With CapTel 840i (and CapTel 840 in 2-line mode), you can turn captions on/off at any time during your call by pressing the CAPTIONS button. When the red light around the CAPTIONS button is lit, you will see captions of everything the other party says.
With CapTel 840 (in 1-Line mode), you must turn the CAPTIONS button on before you dial the phone number. You cannot turn captions on during a call. Simply press the CAPTIONS button (red light around the button is lit) before you dial.
To get captions during an incoming call with the CapTel 840 (in 1-Line mode), your caller must first dial the toll free Captioning Service and enter your phone number in order for you to see captions of the call. Dial-in Numbers for Captioning Service