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