IIRC, from an old Bell Labs record, New York Telephone in NYC had live
>operators annouce the time every 30 seconds circa 1940. The operators
>sat there for 15 or 30 minute shifts and then relieved.
The serivce I remember in NYC was supposed to be something like
637-1212 or maybe 637-TIME, but any 637-xxxx would work.
However, EVERYBODY knew it by memory as NERVOUS (637-8687) and usually dialed it that way.
IIRC, they had announcements every 20 seconds, with the term 'exactly' being used for the on-the-minute announcement.