GPS vs. CDMA
Our products use two different sources as their timing reference - either GPS or CDMA (sometimes called "indirect GPS"). Following are differences between the two methods:
| GPS |
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| This GPS Antenna Kit is included with each Time Server. The standard kit has 50 ft. (15 m) of antenna cable. |
| GPS antenna requires view-of-the-sky with roof or window-mount. Expensive installation and maintenance costs are often required. |
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Worldwide coverage.
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NTP network timing accuracy 1/2 - 2 milliseconds, typical.
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| Absolute timing accuracy of unit is under 30 nanoseconds. For NTP, the network timing accuracy (see above) is more important. |
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Global Positioning System (GPS) is a 32-satellite constellation owned and operated by the United States Government as a national resource.
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| CDMA |
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| The magnetic-mount CDMA antenna is included with each Time Server. It has 12 ft (3.6m) of cable. |
| CDMA antenna works indoors! You can simply place the antenna on top of your equipment rack inside your data center. |
| Localized coverage: USA, China, Korea, Japan and elsewhere. |
| NTP network timing accuracy is 1/2 - 2 milliseconds, typical. (Same as GPS.) |
| Absolute timing accuracy of unit is typically under 10 microseconds. For NTP, the network timing accuracy (see above) is more important. |
| CDMA cellular/PCS mobile telecommunications network via countless CDMA system base stations scattered throughout the world. Maintained by commercial cell phone system providers. CDMA system timing accuracy is guaranteed to be within 10 microseconds in order for the cell phone system to work. |
