PTB Modem Time Service

Last update: April 3, 2024 18:24 UTC (fe4830d85)

Several European countries use the following message data format:

Data format  
0000000000111111111122222222223333333333444444444455555555556666666666777777777 7
0123456789012345678901234567890123456789012345678901234567890123456789012345678 9
1995-01-23 20:58:51 MEZ 10402303260219950123195849740+40000500 *
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›
A year
B month
C day
D hour
E : normally
A for DST to ST switch first hour
B for DST to ST switch second hour if not marked in H
F minute
G second
H timezone
I day of week
J week of year
K day of year
L month for next ST/DST changes
M day
N hour
O UTC year
P UTC month
Q UTC day
R UTC hour
S UTC minute
T modified julian day (MJD)
U DUT1
V direction and month if leap second
W signal delay (assumed/measured)
X sequence number for additional text line in Y
Y additional text
Z on time marker (* - assumed delay / # measured delay)
‹CR›!‹LF› ! is second change !

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 and United Kingdom. Some examples are:

In Germany by Physikalisch-Technische Bundesanstalt (PTB)’s timecode service. Phone number: +49 5 31 51 20 38.
In the UK by National Physical Laboratory (NPL)’s TRUETIME service. Phone number: 0891 516 333
In Italy by Istituto Elettrotecnico Nazionale Galileo Ferrais (ISTC)’s CTD service. Phone number: 166 11 46 15
In Switzerland by Swiss Federal Office of Metrology’s timecode service. Phone number: 031 323 32 25
In Sweden by SP Swedish National Testing and Research Institute’s timecode service. Phone number: +46 33 415783.

Additional Information

Reference Clock Drivers