Motorola T6550 pair.
I can see where this feature can seem somewhat inconsistent. But if you think of it like a phone ringing, it is easier to understand. Once you have answered the phone, the phone stops ringing. And the person who called you never experiences a ring on their end.
Page 26: VibraCall is a vibrating alert that notifies you that your radio is receiving a message. This is useful in noisy environments. When the alert is on, the radio
vibrates once every 30 seconds when you receive a message on the channel and
code you set.
• To turn vibrating alerts on, press menu until the vibrating radio symbol is displayed, then press the plus (+) button to display the letter Y for Yes.
• To turn vibrating alerts off, press menu until the vibrating radio symbol is displayed, then press the minus (-) button until the minus symbol (-) is displayed.