OSF DCE Administration Guide--Core Components
OSF DCE Administration Guide—Core Components
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Type Coverage Inaccuracy Cost
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Telephone
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NIST Regional 10 msec. Variable fee per call
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Radio
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MSF Europe 10 msec. $1K to 2K
WWV North America 100 msec. $1K to 2K
North America &
Europe
WWVB 10 msec. $1K to 2K
Eastern & Central
North Pacific
WWVH 100 msec. $1K to 2K
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Satellite
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GOES Worldwide 1 msec. $2K to $20K
corrected
GPS Worldwide < 100 nsec. $15K to $20K
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C.2 Sources of Coordinated Universal Time
There are several sources of UTC time, including telephone, radio, and satellite, as
described in the following subsections.
C.2.1 Telephone Services
Telephone time-provider services require the time-provider to dial a centralized UTC
time source through a modem. Modem speeds and line delays can affect the accuracy of
the time returned.
Telephone services are usually provided by standards agencies. For example, in the
United States this service is offered by the National Institute of Standards and
Technology (NIST). There is a per-call fee for the service in addition to the cost of the
modem software.
C.2.2 Radio Transmissions
DTS can obtain time from a radio time source. Commercial receivers that monitor time
and frequency broadcasts can return time values through the Time-Provider Interface
(TPI) to the DTS server. The NIST operates the following U.S. time and frequency
stations:
• WWV
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