Royal Observatory of Belgium
Computer Time Code Service

The Royal Observatory distributes time information using telephone lines.
With a personal computer and a modem, connection to that service can be made.
The Full-Time-Format is sent at 1200 baud, 8 data bits, 1 stop bit and no parity.
An explanation about the different items in this time information string will be given at the end of this file.
You can visualize this string with any communications software (like Procomm Plus, Telix, Windows Terminal, ...).

With Windows NT version 3.5x or 4.0, you can synchronize your PC by using TIMESERV 1.3 (included in the Windows NT Resource Kit) .

Example settings of timeserv.ini:

[TimeServ]
Type=EUROPE
Port=\\.\COM3
ModemCommand=ATDTW
Prefix=
PhoneNumber=02 373 0320
timesource=no
Log=yes
SecondaryDomain=
Speed=1200
RandomPrimary=yes
Tasync=no

ATTENTION!!

• The time information is sent for a maximum period of 1 minute.
• It is very important that not only you set the serial port speed to 1200 baud in your communications software, but you must also force your modem to accept only an on-line speed of 1200 baud.
  Depending on the kind of (Hayes-compatible) modem you can try one of the following Hayes-commands:
  

                              ATF4S37=5       (e.g. Bausch) 
                              AT%B1200        (e.g. Datatronics)
                              AT&N2           (e.g. US Robotics)
                              ...
                              (see your modem's users manual)
  

• It is also useful to select Direct Mode ( AT\N1 ).
• If you have an I.B.M.-compatible personal computer with Windows 3.1, you can use a program like Accuset 4.1 to synchronize your computer's clock. To do so, install Accuset and choose the configuration menu to make the necessary adjustments:
  

    Hardware:  - Baud Rate: 1200 BPS
               - Use Alternate Modem Initialization String: fill in the 
                     appropriate Hayes commands for your modem as mentionned 
                     earlier (again it is absolutely necessary to force your 
                     modem to connect at 1200 baud ONLY).
  

    Service:  - Telephone Number: 3730320 or 023730320 if you are calling 
                                  from within Belgium;
                                  003223730320 if you are calling from another
                                  country.
  

  After configuration, you can call our service by clicking the Synchronize Clock button in the main menu.
  When everything is OK, synchronization will be done automatically within a few seconds.
  If synchronization fails the first time, try once more, usually a proper connection is established the second time.
  Accuset 4.1 (shareware) can be found on our FTP-server as a compressed file named acust41.zip

If you have any problems or questions, you can reach us at the following addresses:

• e-mail: labvdp@oma.be
• mail:

  Royal Observatory of Belgium
  

  Labvdp
  Av. Circulaire, 3 - Ringlaan 3
  1180 Bruxelles - Brussel

Tel: 00 32 2 373 02 97
Fax: 00 32 2 373 04 59

TIME INFORMATION STRING:

character column position:
1        10        20                                                       78  80
|        |         |                                                         |  |
1996-05-13 09:41:00 CEST 12013410270319960513074150216+2-030500 ROY.OBS.BEL. *CRLF
|    |  |  | ||  |  |    || |  | | | |   | | | | |    | |  |  | |            ||
A    B  C  D EF  G  H    IJ K  L M N O   P Q R S T    U V  W  X Y            Za
          

<--for direct readout--><------------------packed---------------------------->
<-----------local time><--------UTC---------><-info & time marker->
                                                                                

Applies to local time:

A

year

B

month

C

day

D

hour

E

This position normally contains the usual delimiter ':'.

F

minute

G

second (applies also to UTC time)

H

Local time designation (maximum 4 characters)

        For example:
	
               CEST    Central European Summer Time
               CET     Central European Time

This identifies the time zone where the local time information applies to as well as the state of local time (Daylight Saving Time / Standard Time).

I

day of the week (1=Monday, 2=Tuesday, ...)

J

week of the year

K

day of the year

Next change of local time from Standard Time to Daylight Saving Time or vice versa:

L

month

M

day

N

hour

Applies to UTC:

O

year

P

month

Q

day

R

hour (UTC)

S

minute

T

MJD (day number "Modified Julian Date")

U

DUT1 in tenths of seconds (difference between atomic UTC and astronomical time)

V

is the announcement of a leap second. It contains the sign of the leap second ("+" or "-") and the month of insertion. Leap seconds can be introduced in UTC at the end of December or June.

W

Information about the delay measurement capability (3 character code). For the moment there is no delay measurement capability. Later on it will be possible. The standard advance is 50 ms.

X

is a digit (0 to 9); this is the message sequence number. Its function is to identify which part of the message string is being transmitted in the field that follows.

Y

is one of up to ten parts of a message line with a fixed length of 14 characters. The whole line can consist of any string of visible characters with a length between 14 and 140 in increments of 14. It is transmitted in time multiplex with a maximum repetition period of 10 seconds. The unused characters at the end of the string must be padded with spaces to ensure that the time marker always appears at column 78.

Z

is a visible time marker. Normally it will be the '*'character.

a

Time marker. The exact time reference is the leading edge of the STOP bit of the CR character. All time information collected during the second before, becomes valid at this moment.

Good luck !