What is a radio "PL" (private line) tone used for?

A radio "PL" (private line) tone is primarily utilized to ensure that communication among specific radio users remains confidential and secure from outside interference. This tone allows two ambulances to communicate directly with each other without their conversations being overheard by other units on the same frequency. By employing a PL tone, the radios of the ambulances will only respond to transmissions that include that specific tone, thus filtering out other communications that might disrupt their conversation.

Using PL tones helps in maintaining the privacy of sensitive discussions, which is especially important in emergency medical services where patient confidentiality and operational security are paramount. In contrast, the other options involve broader types of communications that do not necessarily utilize PL tones for privacy, such as general hospital communications or dispatch notifications, which may need to be heard by a wider range of personnel.