The Motorola Quick Call was like the Plectron, a two-tone paging signal that could turn on a beacon, beep the horn, or flash the headlights. The Motorola Syntor radios also had this feature. This was also a feature of the early commercial mobile telephone equipment, before cell phones.
The system jft027 referred to was interruptible tone squelch dialing, where the old telephone dial would interupt a steady squelch tone to open a selective radio receiver. Motorola used a 1500 Hz tone and the ER notification system was called the Hospital Emergency Alert Radio, marketed nationally as the H.E.A.R. system. Other tones were used for selectable law enforcement calling, civil defense, etc.
The system was modified in the last twenty-five years to use dual-tone multi-frequency (DTMF) or Touch-Tone calling.