<p>The <b>refclock_hopf_serial</b> driver supports <ahref="http://www.hopf.com">hopf electronic receivers</a> with serial Interface kompatibel 6021.<br>
</p>
<p>Additional software and information about the software drivers is available from: <ahref="http://www.ATLSoft.de/ntp">http://www.ATLSoft.de/ntp</a>.<br>
</p>
<p>Latest NTP driver source, executables and documentation is maintained at: <ahref="http://www.ATLSoft.de/ntp">http://www.ATLSoft.de/ntp</a></p>
<hr>
<h2><fontsize="+1">Operating System Compatibility</font></h2>
<palign="left">The hopf clock driver has been tested on the following software and hardware platforms:<br> </p>
<tablebgcolor="#C0C0C0">
<tr>
<tdvalign="CENTER"nowrapwidth="23%">
<palign="left"><b>Platform</b></p>
</td>
<tdvalign="CENTER"nowrap>
<palign="left"><b>Operating System</b></p>
</td>
</tr>
<tr>
<tdvalign="CENTER"nowrapwidth="23%">
<palign="left">i386 (PC) </p>
</td>
<tdvalign="CENTER"nowrap>
<palign="left">Linux</p>
</td>
</tr>
<tr>
<tdnowrap>
<palign="left">i386 (PC) </p>
</td>
<tdnowrap>
<palign="left">Windows NT</p>
</td>
</tr>
<tr>
<tdnowrap>
<palign="left">i386 (PC) </p>
</td>
<center>
<tdnowrap>Windows 2000</td>
</center>
</tr>
</table>
<hr>
<h2><fontsize="+1">O/S Serial Port Configuration</font></h2>
The driver attempts to open the device <b><tt><ahref="#REFID">/dev/hopfclock<i>X</i></a></tt></b> where <i><b>X</b></i> is the NTP refclock unit number as defined by the LSB of the refclock address. Valid refclock unit numbers are 0 - 3.
<p>The user is expected to provide a symbolic link to an available serial port device. This is typically performed by a command such as:</p>
<blockquote>
<tt>ln -s /dev/ttyS0 /dev/hopfclock0</tt></blockquote>Windows NT does not support symbolic links to device files. <br>
<b>COMx</b>: is used by the driver, based on the refclock unit number, where <b>unit 1</b> corresponds to <b>COM1</b>: and <b>unit 3</b> corresponds to <b>COM3</b>:<br>
<dd>Specifies the time offset calibration factor, in seconds and fraction, with default 0.0. Should be set to 20 milliseconds to correct serial line and operating system delays incurred in capturing time stamps from the synchronous packets.
<p>as specified in clock manual under pt. <u>[ <spanstyle="font-size:10.0pt;font-family: Arial;mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:"Times New Roman"; mso-ansi-language:EN-GB;mso-fareast-language:DE;mso-bidi-language:AR-SA"lang="EN-GB"><b>Data String for NTP</b> ( <b><i>Network Time Protocol </i></b>) </span>]</u></p>