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Reference Clock Drivers
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Reference Clock Drivers
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<p><h4>Introduction</h4>

<p>Support for most of the commonly available radio and modem clocks is
included in the default configuration of the NTP daemon for Unix
<code>xntpd</code>. Individual clocks can be activated by configuration
file commands, specifically the <code>server</code> and
<code>fudge</code> commands described in the <a
href="xntpd.html"><code>xntpd</code> program manual page</a>. The
following discussion presents Information on how to select and configure
the device drivers in a running Unix system.

<p>Radio and modem clocks by convention have addresses in the form
127.127.<var>t.u</var>, where <var>t</var> is the clock type and
<var>u</var> is a unit number in the range 0-3 used to distinguish
multiple instances of clocks of the same type. Most of these clocks
require support in the form of a serial port or special bus peripheral.
The particular device is normally specified by adding a soft link
<code>/dev/device<i>u</i></code> to the particular hardware device
involved, where <code><i>u</i></code> correspond to the unit number
above.

<p>Following is a list showing the type and title of each driver
currently implemented. The compile-time identifier for each is shown in
parentheses. Click on a selected type for specific description and
configuration documentation, including the clock address, reference ID,
driver ID, serial port device name and speed, and features (line
disciplines, etc.). For those drivers without specific documentation,
please contact the author listed in the <a
href="copyright.html">copyright page</a>.

<p><a href="driver1.html">Type 1</a> Local Clock Driver
(<code>LOCAL_CLOCK</code>)
<br><a href="driver2.html">Type 2</a> Trak 8820 GPS Receiver
(<code>TRAK</code>)
<br><a href="driver3.html">Type 3</a> PSTI/Traconex 1020 WWV/WWVH
Receiver (<code>PST</code>)
<br><a href="driver4.html">Type 4</a> Spectracom 8170 and Netclock/2
WWVB Receivers (<code>WWVB</code>)
<br><a href="driver5.html">Type 5</a> TrueTime GPS/GOES/OMEGA Receivers
(<code>TRUETIME</code>)
<br><a href="driver6.html">Type 6</a> IRIG Audio Decoder (Sun only)
(<code>IRIG</code>)
<br><a href="driver7.html">Type 7</a> Scratchbuilt CHU Receiver
(<code>CHU</code>)
<br><a href="driver8.html">Type 8</a> Generic Reference Driver
(<code>PARSE</code>)
<br><a href="driver9.html">Type 9</a> Magnavox MX4200 GPS Receiver
(<code>MX4200</code>)
<br><a href="driver10.html">Type 10</a> Austron 2200A/2201A GPS
Receivers (<code>AS2201</code>)
<br><a href="driver11.html">Type 11</a> Arbiter 1088A/B GPS Receiver
(<code>ARBITER</code>)
<br><a href="driver12.html">Type 12</a> KSI/Odetics TPRO/S IRIG
Interface (Sun only) (<code>TPRO</code>)
<br>Type 13 Leitch CSD 5300 Master Clock Controller
(<code>LEITCH</code>)
<br>Type 14 EES M201 MSF Receiver (<code>MSFEES</code>)
<br><a href="driver5.html">Type 15</a> * TrueTime TM-TMD GPS Receiver
<br>Type 16 Bancomm GPS/IRIG Receiver (HP only) (<code>BANC</code>)
<br>Type 17 Datum Precision Time System (<code>DATUM</code>)
<br><a href="driver18.html">Type 18</a> NIST Modem Time Service
(<code>ACTS</code>)
<br><a href="driver19.html">Type 19</a> Heath WWV/WWVH Receiver
(<code>HEATH</code>)
<br><a href="driver20.html">Type 20</a> Generic NMEA GPS Receiver (<code>NMEA</code>)
<br>Type 21 TrueTime GPS-VME Interface (HP only) (<code>GPSVME</code>)
<br><a href="driver22.html">Type 22</a> PPS Clock Discipline
(<code>ATOM</code>)
<br><a href="driver23.html">Type 23</a> PTB Modem Time Service
(<code>PTBACTS</code>)
<br><a href="driver24.html">Type 24</a> USNO Modem Time Service
(<code>USNO</code>)
<br><a href="driver5.html">Type 25</a> * TrueTime generic receivers
<br><a href="driver26.html">Type 26</a> Hewlett Packard 58503A GPS
Receiver (<code>HPGPS</code>)
<br><a href="driver27.html">Type 27</a> Arcron MSF Receiver
(<code>ARCRON_MSF</code>)
<br><a href="driver28.html">Type 28</a> Shared memory driver
(<code>SHM</code>)

<p>* All TrueTime receivers are now supported by one driver, type 5.
Types 15 and 25 will be retained only for a limited time and may be
reassigned in future.

<p>Additional Information

<p><a href = "prefer.html">Mitigation Rules and the <code>prefer</code>
Keyword</a>
<br><a href="rdebug.html">Debugging Hints for Reference Clock
Drivers</a>
<br><a href="ldisc.html">Line Disciplines and Streams Drivers</a>
<br><a href="pps.html">Pulse-per-second (PPS) Signal Interfacing</a>
<br><a href="howto.html">How To Write a Reference Clock Driver</a>
<br><a href="index.html">The Network Time Protocol (NTP) Distribution
</a>

<hr><address>David L. Mills (mills@udel.edu)</address></body></html>
