We had a similar time service in Uruguay and, whenever we had an important appointment (e.g., a medical one) we’d call the number to make sure our clocks and watches were on time.

It was a female voice that said something that could be translated to “the signal will mark it is <time>,” and, the funny thing is, between the way it had been recorded and the fact that signal (señal) and lady (señora) can sound very similar in Spanish when over the phone and followed by a vowel (“indicará” for will mark in this case), a lot of us thought it said “the lady will mark” and, as a little kid, I thought there was an old time-keeping lady on whom we all depended to be in sync. Miss NTP I guess!