NTP PARSE clock data formats
Last update: November 23, 2022 17:49 UTC (1b4d24aef)
The parse driver currently supports several clocks with different query mechanisms. In order for you to find a sample that might be similar to a clock you might want to integrate into parse I’ll sum up the major features of the clocks (this information is distributed in the parse/clk_*.c and ntpd/refclock_parse.c files).
Table of Contents
Meinberg clocks
Meinberg: start=, end=, sync on start
pattern="\2D: . . ;T: ;U: . . ; \3"
pattern="\2 . . ; ; : : ; \3"
pattern="\2 . . ; ; : : ; : ; ; . . "
Meinberg is a German manufacturer of time code receivers. Those clocks have a pretty common output format in the stock version. In order to support NTP Meinberg was so kind to produce some special versions of the firmware for the use with NTP. So, if you are going to use a Meinberg clock please ask whether there is a special Uni Erlangen version. You can reach Meinberg via the Web. Information can also be ordered via email.
General characteristics
Meinberg clocks primarily output pulse per second and a describing ASCII string. This string can be produced in two modes: either upon the reception of a question mark or every second. NTP uses the latter mechanism. DCF77 AM clocks have a limited accuracy of a few milliseconds. The DCF77 PZF5xx variants provide higher accuracy and have a pretty good relationship between RS232 time code and the PPS signal. Except for early versions of the old GPS166 receiver type, Meinberg GPS receivers have a very good timing relationship between the datagram and the pulse. The beginning of the start bit of the first character has basically the same accuracy as the PPS signal, plus a jitter of up to 1 bit time depending on the selected baud rate, i.e. 52 μs @ 19200. PPS support should always be used, if possible, in order to yield the highest possible accuracy.
The preferred tty setting for Meinberg DCF77 receivers is 9600/7E2:
CFLAG (B9600|CS7|PARENB|CREAD|HUPCL)
IFLAG (IGNBRK|IGNPAR|ISTRIP)
OFLAG 0
LFLAG 0
The tty setting for Meinberg GPS16x/17x receivers is 19200/8N1:
CFLAG (B19200|CS8|PARENB|CREAD|HUPCL)
IFLAG (IGNBRK|IGNPAR|ISTRIP)
OFLAG 0
LFLAG 0
All clocks should be run at datagram once per second.
Format of the Meinberg standard time string:
<STX>_D:dd.mm.yy;T:w;U:hh.mm.ss;uvxy_<ETX>pos: 0 000000001111111111222222222233 31 234567890123456789012345678901 2
where:
| Variable |
Description |
<STX> |
start-of-text, ASCII code 0x02 |
dd.mm.yy |
day of month, month, year of the century, separated by dots |
w |
day of week (1..7, Monday = 1) |
hh:mm:ss |
hour, minute, second, separated by dots |
u |
# for GPS receivers: time is not synchronized
# for older PZF5xx receivers: no correlation, not synchronized
# for other devices: never synced since powerup
' ' if nothing of the above applies |
v |
* for GPS receivers: position has not been verified
* for other devices: freewheeling based on internal quartz
' ' if none of the above applies |
x |
U if UTC time is transmitted
S if daylight saving time is active
' ' if none of the above applies |
y |
! during the hour preceding start or end of daylight saving time
A during the hour preceding a leap second
' ' if none of the above applies |
<ETX> |
end-of-text, ASCII code 0x03 |
Format of the Uni Erlangen time string for PZF5xx receivers:
<STX>_dd.mm.yy; w; hh:mm:ss; tuvxyza_<ETX>pos: 0 000000001111111111222222222233 31 234567890123456789012345678901 2
where:
| Variable |
Description |
<STX> |
start-of-text, ASCII code 0x02 |
dd.mm.yy |
day of month, month, year of the century, separated by dots |
w |
day of week (1..7, Monday = 1) |
hh:mm:ss |
hour, minute, second, separated by colons |
t |
U if UTC time is transmitted, else ' ' |
u |
# for older PZF5xx receivers: no correlation, not synchronized
# for PZF511 and newer: never sync’ed since powerup
' ' if none of the above applies |
v |
* if freewheeling based on internal quartz, else ' ' |
x |
S if daylight saving time is active, else ' ' |
y |
! during the hour preceding start or end of daylight saving time, else ' ' |
z |
A during the hour preceding a leap second, else ' ' |
a |
R alternate antenna (reminiscent of PZF5xx), usually ' ' for GPS receivers |
<ETX> |
end-of-text, ASCII code 0x03 |
Format of the Uni Erlangen time string for GPS16x/GPS17x receivers:
<STX>_dd.mm.yy; w; hh:mm:ss; +uu:uu; uvxyzab; ll.lllln lll.lllle hhhh_m<ETX>pos: 0 0000000011111111112222222222333333333344444444445555555555666666 61 2345678901234567890123456789012345678901234567890123456789012345 6
where:
| Variable |
Description |
<STX> |
start-of-text, ASCII code 0x02 |
dd.mm.yy |
day of month, month, year of the century, separated by dots |
w |
day of week (1..7, Monday = 1) |
hh:mm:ss |
hour, minute, second, separated by colons |
+uu:uu |
offset to UTC in hours and minutes, preceded by + or - |
u |
# if time is not synchronized, else ' ' |
v |
* if position has not been verified, else ' ' |
x |
S if daylight saving time is active, else ' ' |
y |
! during the hour preceding start or end of daylight saving time, else ' ' |
z |
A during the hour preceding a leap second, else ' ' |
a |
R alternate antenna (reminiscent of PZF5xx), usually ' ' for GPS receivers |
b |
L during a leap second, i.e. if the seconds field is 60, else ' ' |
ll.lllln |
position latitude in degrees, n can actually be N or S, i.e. North or South |
lll.lllle |
position longitude in degrees, e can actually be E or W, i.e. East or West |
hhhh |
position altitude in meters, always followed by m |
<ETX> |
end-of-text, ASCII code 0x03 |
Examples for Uni Erlangen strings from GPS receivers:
\x02 09.07.93; 5; 08:48:26; +00:00; ; 49.5736N 11.0280E 373m \x03
\x02 08.11.06; 3; 14:39:39; +00:00; ; 51.9828N 9.2258E 176m \x03
The Uni Erlangen formats should be used preferably. Newer Meinberg GPS receivers can be configured to transmit that format, for older devices there may be a special firmware version available.
For the Meinberg parse look into clk_meinberg.c.
Raw DCF77 Data via serial line
RAWDCF: end=TIMEOUT>1.5s, sync each char (any char),generate pseudo time codes, fixed format
direct DCF77 code input
In Europe it is relatively easy/cheap to receive the German time code transmitter DCF77. The simplest version to process its signal is to feed the 100/200ms pulse of the demodulated AM signal via a level converter to an RS232 port at 50Baud. parse/clk_rawdcf.c holds all necessary decoding logic for the time code which is transmitted each minute for one minute. A bit of the time code is sent once a second.
The preferred tty setting is:
CFLAG (B50|CS8|CREAD|CLOCAL)
IFLAG 0
OFLAG 0
LFLAG 0
DCF77 raw time code
From “Zur Zeit”, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig und Berlin, März 1989
Timecode transmission for AM:
- time marks are sent every second except for the second before the next minute mark
- time marks consist of a reduction of transmitter power to 25% of the nominal level
- the falling edge is the time indication (on time)
- time marks of a 100ms duration constitute a logical 0
- time marks of a 200ms duration constitute a logical 1
see the spec. (basically a (non-)inverted pseudo random phase shift) encoding:
For FM:
| Second |
Contents |
| 0 - 10 |
AM: free
FM: 0 |
| 11 - 14 |
free |
| 15 |
R - alternate antenna |
| 16 |
A1 - expect zone change (1 hour before) |
| 17 - 18 |
Z1, Z2 - time zone
0 0 illegal
0 1 MEZ (MET)
1 0 MESZ (MED, MET DST)
1 1 illegal |
| 19 |
A2 - expect leap insertion/deletion (1 hour before) |
| 20 |
S - start of time code (1) |
| 21 - 24 |
M1 - BCD (lsb first) Minutes |
| 25 - 27 |
M10 - BCD (lsb first) 10 Minutes |
| 28 |
P1 - Minute Parity (even) |
| 29 - 32 |
H1 - BCD (lsb first) Hours |
| 33 - 34 |
H10 - BCD (lsb first) 10 Hours |
| 35 |
P2 - Hour Parity (even) |
| 36 - 39 |
D1 - BCD (lsb first) Days |
| 40 - 41 |
D10 - BCD (lsb first) 10 Days |
| 42 - 44 |
DW- BCD (lsb first) day of week (1: Monday -> 7: Sunday) |
| 45 - 49 |
MO1 - BCD (lsb first) Month |
| 50 |
MO10 - 10 Months |
| 51 - 53 |
Y1 - BCD (lsb first) Years |
| 54 - 57 |
Y10 - BCD (lsb first) 10 Years |
| 58 |
P3 - Date Parity (even) |
| 59 |
usually missing (minute indication), except for leap insertion |
Schmid clock
Schmid clock: needs poll, binary input, end=\xFC, sync start
The Schmid clock is a DCF77 receiver that sends a binary time code at the reception of a flag byte. The contents if the flag byte determined the time code format. The binary time code is delimited by the byte 0xFC.
TTY setup is:
CFLAG (B1200|CS8|CREAD|CLOCAL)
IFLAG 0
OFLAG 0
LFLAG 0
The command to Schmid’s DCF77 clock is a single byte; each bit allows the user to select some part of the time string, as follows (the output for the lsb is sent first).
| Bit |
Description |
0 |
time in MEZ, 4 bytes binary, not BCD; hh.mm.ss.tenths |
1 |
date 3 bytes binary, not BCD: dd.mm.yy |
2 |
week day, 1 byte (unused here) |
3 |
time zone, 1 byte
0=MET
1=MEST. (unused here) |
4 |
clock status, 1 byte
0=time invalid
1=time from crystal backup
3=time from DCF77 |
5 |
transmitter status, 1 byte
bit 0: backup antenna
bit 1: time zone change within 1h
bit 3,2: TZ 01=MEST, 10=MET
bit 4: leap second will be added within one hour
bits 5-7: Zero |
6 |
time in backup mode, units of 5 minutes (unused here) |
Trimble SV6 ASCII time code (TAIP)
Trimble SV6: needs poll, ascii timecode, start=>, end=<, query=>QTM<, eol=<
Trimble SV6 is a GPS receiver with PPS output. It needs to be polled. It also need a special tty mode setup (EOL=<).
TTY setup is:
CFLAG (B4800|CS8|CREAD)
IFLAG (BRKINT|IGNPAR|ISTRIP|ICRNL|IXON)
OFLAG (OPOST|ONLCR)
LFLAG (ICANON|ECHOK)
Special flags are:
PARSE_F_PPSPPS - use CIOGETEV for PPS time stamping
PARSE_F_PPSONSECOND - the time code is not related to the PPS pulse (so use the time code only for the second epoch)
Timecode
0000000000111111111122222222223333333 / char
0123456789012345678901234567890123456 \ posn
>RTMhhmmssdddDDMMYYYYoodnnvrrrrr;*xx< Actual
----33445566600112222BB7__-_____--99- Parse
>RTM 1 ;* < Check
ELV DCF7000
ELV DCF7000: end=\r, pattern= - - - - - - - \r
The ELV DCF7000 is a cheap DCF77 receiver sending each second a time code (though not very precise!) delimited by \r.
Timecode
YY-MM-DD-HH-MM-SS-FF\r
FF&0x1 - DST
FF&0x2 - DST switch warning
FF&0x4 - unsynchronised
HOPF 6021 und Kompatible
HOPF Funkuhr 6021 mit serieller Schnittstelle Created by F.Schnekenbuehl from clk_rcc8000.c Nortel DASA Network Systems GmbH, Department: ND250 A Joint venture of Daimler-Benz Aerospace and Nortel.
hopf Funkuhr 6021
used with 9600,8N1,
UTC via serial line
"Sekundenvorlauf" ON
ETX zum Sekundenvorlauf ON
dataformat 6021
output time and date
transmit with control characters
transmit evry second
Type 6021 Serial Output format
000000000011111111 / char
012345678901234567 \ position
sABHHMMSSDDMMYYnre Actual
C4110046231195 Parse
s enr Check
s = STX (0x02), e = ETX (0x03)
n = NL (0x0A), r = CR (0x0D)
A B - Status and weekday
A - Status
8 4 2 1
x x x 0 - no announcement
x x x 1 - Summertime - wintertime - summertime announcement
x x 0 x - Wintertime
x x 1 x - Summertime
0 0 x x - Time/Date invalid
0 1 x x - Internal clock used
1 0 x x - Radio clock
1 1 x x - Radio clock highprecision
B - 8 4 2 1
0 x x x - MESZ/MEZ
1 x x x - UTC
x 0 0 1 - Monday
x 0 1 0 - Tuesday
x 0 1 1 - Wednesday
x 1 0 0 - Thursday
x 1 0 1 - Friday
x 1 1 0 - Saturday
x 1 1 1 - Sunday
Diem Computime Clock
The Computime receiver sends a datagram in the following format every minute
Timestamp T:YY:MM:MD:WD:HH:MM:SSCRLF
Pos 0123456789012345678901 2 3
0000000000111111111122 2 2
Parse T: : : : : : : \r\n
T Startcharacter "T" specifies start of the timestamp
YY Year MM Month 1-12
MD Day of the month
WD Day of week
HH Hour
MM Minute
SS Second
CR Carriage return
LF Linefeed
WHARTON 400A Series Clock with a 404.2 Serial interface
The WHARTON 400A Series clock is able to send date/time serial messages in 7 output formats. We use format 1 here because it is the shortest. We set up the clock to send a datagram every second. For use with this driver, the WHARTON 400A Series clock must be set-up as follows :
Programmable Selected
Option No Option
BST or CET display 3 9 or 11
No external controller 7 0
Serial Output Format 1 9 1
Baud rate 9600 bps 10 96
Bit length 8 bits 11 8
Parity even 12 E
WHARTON 400A Series output format 1 is as follows :
Timestamp STXssmmhhDDMMYYSETX
Pos 0 12345678901234
0 00000000011111
STX start transmission (ASCII 0x02)
ETX end transmission (ASCII 0x03)
ss Second expressed in reversed decimal (units then tens)
mm Minute expressed in reversed decimal
hh Hour expressed in reversed decimal
DD Day of month expressed in reversed decimal
MM Month expressed in reversed decimal (January is 1)
YY Year (without century) expressed in reversed decimal
S Status byte : 0x30 +
bit 0 0 = MSF source 1 = DCF source
bit 1 0 = Winter time 1 = Summer time
bit 2 0 = not synchronised 1 = synchronised
bit 3 0 = no early warning 1 = early warning