This was, of course, in the days prior to the automated systems that were in use, beginning in the late-1940s. The automated systems would be synced to a clock, and they would play the appropriate time, followed by a tone.

One such system employed a series of looped tape cartridges (known in broadcasting as "carts") that would trip in sequence when an inaudible cue tone triggered the next tape in the deck. For example:

"At the tone, the time will be..." "Four..." "Forty-eight..." "And ten seconds." BEEP

I remember my father calling Time every Sunday evening, when it was time to wind up our clocks (My parents collected antique clocks). I still remember the phone number: (714)853-1212. It still works today, only now it includes the date and temperature, and it's sponsored, so you'll have to sit through an ad.