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https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwv/telephone-time-day-service

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Physical Measurement LaboratoryTime and Frequency Division

## Time Realization and Distribution Group

-  Radio Station WWV  Expand or Collapse    -  History of Radio Station WWV 
  -  Manufacturers of Time and Frequency Receivers 
  -  NIST Radio Broadcasts Frequently Asked Questions (FAQ) 
  -  Telephone Time-of-Day Service  Expand or Collapse      -  Telephone Time-of-Day Service (2019) 
    -  Telephone Time-of-Day Service (2020) 
  -  WWV Photos 
  -  WWV and WWVH Broadcast Outages 
  -  WWV and WWVH Digital Time Code and Broadcast Format 
  -  WWV/WWVH Station Library 

# Telephone Time-of-Day Service

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The audio portions of the WWV and WWVH broadcasts can also be heard by telephone. The time announcements are normally delayed by less than 30 ms when using land lines from within the continental United States, and the stability (delay variation) is generally < 1 ms. When mobile phones or voice over IP networks are used, the delays can be as large as 150 ms. In the very rare instances when the telephone connection is made by satellite, the time is delayed by more than 250 ms.

To hear these broadcasts, dial **(303) 499-7111** for WWV (Colorado), and **(808) 335-4363** for WWVH (Hawaii). Callers are disconnected after 2 minutes. These are not toll-free numbers; callers outside the local calling area are charged for the call at regular long-distance rates.

The telephone time-of-day service is used to synchronize clocks and watches and for the calibration of stopwatches and timers. It receives about 1,000 calls per day.

### Outages

Time and frequency

## Contacts

                -      NIST Radio    nist.radio@boulder.nist.gov   

-  **‹** NIST Radio Broadcasts Frequently Asked Questions (FAQ) 
-  Telephone Time-of-Day Service (2019) **›** 

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