Back in the day, I purchased a telephone-answering machine with a prerecorded message that used a male voice. When my mother returned from vacation, I forgot to mention it to her.
The next Saturday, the phone rang and the machine answered. After the message, there was a pause and the caller hung up. A second time and the same result.
Then the phone rang a third time. I heard, "This is your mother, I think. If I am, please call me."