transmission speed of COM0 or COM1 can be measured.
The format of the output string is ASCII, see the technical specifications at the end of this document for
details. If the capture buffer is full a message "** capture buffer full" is transmitted, if the interval between two
captures is too short the warning "** capture overrun" is being sent.
3.4 Asynchronous Serial Ports (optional 4x COM)
Four asynchronous serial RS232 interfaces (COM0 ... COM3) are available to the user. In the default mode
of operation, the serial outputs are disabled until the receiver has synchronized after power-up. However, the
system can be configured to enable those outputs immediately after power-up. Transmission speeds, framings
and mode of operation can be configured separately using the setup menu. COM0 is compatible with other
radio remote clocks made by Meinberg. It sends the time string either once per second, once per minute or on
request with ASCII ´?´ only. Also the interfaces can be configured to transmit capture data either automatically
when available or on request. The format of the output strings is ASCII, see the technical specifications at the
end of this document for details. A separate document with programming instructions can be requested defining
a binary data format which can be used to exchange parameters with GPS180 via COM0.
3.5 DCF77 Emulation
The clock generates TTL level time marks (active HIGH) which are compatible with the time marks spread by
the German long wave transmitter DCF77. This long wave transmitter installed in Mainflingen near Frank-
furt/Germany transmits the reference time of the Federal Republic of Germany: time of day, date of month and
day of week in BCD coded second pulses. Once every minute the complete time information is transmitted.
However, the generates time marks representing its local time as configured by the user, including announce-
ment of changes in daylight saving and announcement of leap seconds. The coding sheme is given below:
M
Start of Minute (0.1 s)
R
RF Transmission via secondary antenna
A1
Announcement of a change in daylight saving
Z1, Z2
Time zone identification
Z1, Z2 = 0, 1:
Daylight saving disabled
Z1, Z2 = 1, 0:
Daylight saving enabled
A2
Announcement of a leap second
S
Start of time code information
P1, P2, P3
Even parity bits
0
10
20
30
40
50
R
M
1
4
2
1
20
10
8
4
2
1
P
2
0
2
0
1
8
4
2
1
2
4
8
10
1
2
4
8
10
2
0
4
0
8
0
3
P
A1
Z1
Z2
A2
S
1
2
4
8
1
0
2
0
4
0
1
P
Minute
(reserved)
Hour
Day of Month
Day of Week
Year of the Century
Month of Year
Time marks start at the beginning of new second. If a binary "0" is to be transmitted, the length of the
corresponding time mark is 100 msec, if a binary "1" is transmitted, the time mark has a length of 200 msec. The
information on the current date and time as well as some parity and status bits can be decoded from the time
marks of the 15th up to the 58th second every minute. The absence of any time mark at the 59th second of a
minute signals that a new minute will begin with the next time mark. The DCF emulation output is enabled
immediately after power-up.
3.6 Programmable pulse
At the male connector Typ VG96 there are four programmable TTL outputs (Prog Pulse 0-3), which are arbitrarily
programmable.
4
Date: 21st June 2017
GPS180SV
