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< TITLE > PTB Modem Time Service < / TITLE >
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< 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 >
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< DL >
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< 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 >
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< P > Additional Information< / P >
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< 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 >
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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 >
1999-12-09 13:01:21 +00:00
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< ADDRESS > by Marco Mascarello (masca@tf.ien.it) for David L. Mills
(mills@udel.edu)< / ADDRESS >
1999-12-09 13:01:21 +00:00
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