C. Crane DAR-101 - Manual (Page 21)

20
GB
7. Rotate the Tuning control to select REC BEEP and press the
Enter button to enter the setting. Rotate the Tuning control to
choose ON, and press the Enter button to confirm the setting.
This will allow you to insert a BEEP tone when the recorder starts
recording a phone call. This will help advise both parties they are
being recorded and may be required by law.
Note:
It may be illegal to record a call without both parties knowledge
and consent. Please check with your local law enforcement.