Voice announcements of Eastern Time are made at ten-second intervals, followed by a tone whose beginning indicates the exact time. This service is available to the general public by dialling the Ottawa telephone numbers 613-745-1576 for English service and 613-745-9426 for French service.
The time signal also "ticks" each second to facilitate accurate counting down for setting digital chronometers. Three announcements are given, and the caller is then disconnected. The lines are busiest between 7 a.m. and 9 a.m., and 4 p.m. and 7 p.m., so callers are encouraged to make their time checks at other times, if possible. Long distance charges apply for calls originating from locations outside the Ottawa area, and the caller is responsible for these charges. The NRC's time laboratory has sought to expand this service Canada-wide on a no-charge basis, but every option examined to date has been too expensive.
The telephone time signals described above may be routed via one or two communications satellite hops, being delayed by 0.25 seconds per hop.