179 lines
5.3 KiB
HTML
179 lines
5.3 KiB
HTML
<HTML>
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<HEAD>
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<META NAME="GENERATOR" CONTENT="Adobe PageMill 3.0 per Windows">
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
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<TITLE>PTB Modem Time Service </TITLE>
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</HEAD>
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<BODY>
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<H3>PTB Modem Time Service and other European Laboratories Time
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Services</H3>
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<HR ALIGN=LEFT>
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<H4>Synopsis</H4>
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<P>Address: 127.127.23.<I>u</I> <BR>
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Reference ID: <TT>PTB</TT> <BR>
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Driver ID: <TT>ACTS_PTB</TT><BR>
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Serial Port: <TT>/dev/ptb<I>u</I></TT>; 1200 baud, 8-bits, no
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parity <BR>
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Requires: <TT>/usr/include/sys/termios.h</TT> header file with
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modem control</P>
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<H4>Description</H4>
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<P>This driver supports the PTB Automated Computer Time Service
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(ACTS) and it is a modified version of the NIST ACTS driver so
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see it for more informations..</P>
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<P>It periodically dials a prespecified telephone number, receives
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the PTB timecode data and calculates the local clock correction.
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It designed primarily for use when neither a radio clock nor connectivity
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to Internet time servers is available. For the best accuracy,
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the individual telephone line/modem delay needs to be calibrated
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using outside sources.</P>
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<P>The only change between this driver and the NIST one is the
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data format. Infact PTB data format is the following:</P>
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<P><FONT SIZE="-1" FACE="Courier New">Data format<BR>
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0000000000111111111122222222223333333333444444444455555555556666666666777777777
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7<BR>
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0123456789012345678901234567890123456789012345678901234567890123456789012345678
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9<BR>
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1995-01-23 20:58:51 MEZ 10402303260219950123195849740+40000500
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*<BR>
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A B C D EF G H IJ K L M N O P Q R S T U V W
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XY Z<CR><LF><BR>
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A year<BR>
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B month<BR>
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C day<BR>
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D hour<BR>
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E : normally<BR>
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A for DST to ST switch first hour<BR>
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B for DST to ST switch second hour if not marked in H<BR>
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F minute<BR>
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G second<BR>
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H timezone<BR>
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I day of week<BR>
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J week of year<BR>
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K day of year<BR>
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L month for next ST/DST changes<BR>
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M day<BR>
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N hour<BR>
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O UTC year<BR>
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P UTC month<BR>
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Q UTC day<BR>
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R UTC hour<BR>
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S UTC minute<BR>
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T modified julian day (MJD)<BR>
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U DUT1<BR>
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V direction and month if leap second<BR>
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W signal delay (assumed/measured)<BR>
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X sequence number for additional text line in Y<BR>
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Y additional text<BR>
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Z on time marker (* - assumed delay / # measured delay)<BR>
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<CR>!<LF> ! is second change !<BR>
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</FONT><BR>
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This format is an ITU-R Recommendation (ITU-R TF583.4) and is now available from the primary
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timing centres of the following countries:
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Austria, Belgium, Germany, Italy, The Netherlands, Poland, Portugal, Romania, Spain, Sweden,
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Switzerland, Turkey, United Kingdom.
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Some examples are:
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</P>
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<UL>
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<LI>In Germany by Physikalisch-Technische Bundesanstalt (PTB)'s
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timecode service. Phone number: +49 5 31 51 20 38.
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</UL>
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<BLOCKQUOTE>
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<P>For more detail, see <A HREF="http://www.ptb.de/english/org/4/43/433/disse.htm">http://www.ptb.de/english/org/4/43/433/disse.htm</A></P>
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</BLOCKQUOTE>
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<UL>
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<LI>In the UK by National Physical Laboratory (NPL)'s TRUETIME
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service. Phone number: 0891 516 333
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</UL>
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<BLOCKQUOTE>
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<P>For more detail, see <A HREF="http://www.npl.co.uk/npl/ctm/truetime.html">http://www.npl.co.uk/npl/ctm/truetime.html</A></P>
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</BLOCKQUOTE>
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<UL>
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<LI>In Italy by Istituto Elettrotecnico Nazionale "Galileo
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Ferrais" (IEN)'s CTD service. Phone number: 166 11 46
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15
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</UL>
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<BLOCKQUOTE>
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<P>For more detail, see <A HREF="http://www.ien.it/tf/time/Pagina42.html">http://www.ien.it/tf/time/Pagina42.html</A></P>
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</BLOCKQUOTE>
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<UL>
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<LI>In Switzerland by Swiss Federal Office of Metrology 's timecode
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service. Phone number: 031 323 32 25
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</UL>
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<BLOCKQUOTE>
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<P>For more detail, see <A HREF="http://www.ofmet.admin.ch/de/labors/4/Zeitvert.html%20">http://www.ofmet.admin.ch/de/labors/4/Zeitvert.html
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</A></P>
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</BLOCKQUOTE>
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<UL>
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<LI>In Sweden by SP Swedish National Testing and Research Institute
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's timecode service. Phone number: +46 33 415783
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</UL>
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<BLOCKQUOTE>
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<P>For more detail, see <A HREF="http://www.sp.se/pne/ElectricalMetrology/ElMeteng/frameset.htm">http://www.sp.se/pne/ElectricalMetrology/ElMeteng/frameset.htm</A><BR>
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<BR>
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</P>
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</BLOCKQUOTE>
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<H4>Fudge Factors</H4>
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<DL>
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<DT><TT>time1 <I>time</I></TT>
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<DD>Specifies the time offset calibration factor, in seconds
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and fraction, with default 0.0.
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<DT><TT>time2 <I>time</I></TT>
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<DD>Not used by this driver.
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<DT><TT>stratum <I>number</I></TT>
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<DD>Specifies the driver stratum, in decimal from 0 to 15, with
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default 0.
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<DT><TT>refid <I>string</I></TT>
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<DD>Specifies the driver reference identifier, an ASCII string
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from one to four characters, with default PTB.
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<DT><TT>flag1 0 | 1</TT>
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<DD>Not used by this driver.
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<DT><TT>flag2 0 | 1</TT>
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<DD>Not used by this driver.
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<DT><TT>flag3 0 | 1</TT>
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<DD>Not used by this driver.
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<DT><TT>flag4 0 | 1</TT>
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<DD>Not used by this driver.
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</DL>
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<P>Additional Information</P>
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<P>A keyword in the ntp.conf file permits a direct connection
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to a serial port of source of time like IEN CTD signal. It is
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sufficient to use the string DIRECT in place of the phone number.</P>
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<P>Example:</P>
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<P><FONT FACE="Courier New">server 127.127.23.1</FONT></P>
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<P><FONT FACE="Courier New">phone DIRECT</FONT></P>
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<P><A HREF="refclock.htm">Reference Clock Drivers</A> <HR ALIGN=LEFT></P>
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<ADDRESS>by Marco Mascarello (masca@tf.ien.it) for David L. Mills
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(mills@udel.edu)</ADDRESS>
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</BODY>
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</HTML>
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