Following are examples of the serial timecode formats used by the various manufacturers as given in the instruction manauals. These examples are intended only for illustration and not as the basis of system design. The following symbols are used to identify the timecode character that begins a subfield. The values given after this symbol represent the character offset from the beginning of the timecode string.
C on-time character (start bit) T time of day D day of year or month/day A alarm indicator (format specific) Q quality indicator (format specific)
In order to promote uniform behavior in the various implementations, it is useful to have a common interpretation of alarm conditions and signal quality. When the alarm indicator it on, the receiver is not operating correctly or has never synchronized to the broadcast signal. When the alarm indicator is off and the quality indicator is on, the receiver has synchronized to the broadcast signal, then lost the signal and is coasting on its internal oscillator.
"<cr><lf>i ddd hh:mm:ss TZ=zz<cr><lf>"
C A D T
poll: "T"; offsets: T = 7, D = 3, A = 0, Q = none
i = synchronization flag (" " = in synch, "?" = out synch)
ddd = day of year
hh:mm:ss = hours, minutes, seconds
zz = timezone offset (hours from UTC)
note: alarm condition is indicated by other than " " at A, which
occurs during initial synchronization and when received signal has
been lost for about ten hours
example: " 216 15:36:43 TZ=0"
A D T
"<cr><lf>iqyy ddd hh:mm:ss.fff ld"
C AQD T
poll: "T"; offsets: T = 9, D = 2, A = 0, Q = 1
i = synchronization flag (" " = in synch, "?" = out synch)
q = quality indicator (" " = locked, "A"..."D" = unlocked)
yy = year (as broadcast)
ddd = day of year
hh:mm:ss.fff = hours, minutes, seconds, milliseconds
l = leap-second warning ("L" indicates leap at end of month)
d = daylight time indicator (see manual)
note: alarm condition is indicated by other than " " at A, which
occurs during initial synchronization and when received signal has
been lost for about ten hours; unlock condition is indicated by
other than " " at Q
example: " 216 15:36:43.640 D"
AQ D T
"<cr><lf><^a>ddd:hh:mm:ssq<cr>"
D T QC
poll: none; offsets: T = 4, D = 0, A = 12, Q = 12
hh:mm:ss = hours, minutes, seconds
q = quality/alarm indicator (" " = locked, "?" = alarm)
note: alarm condition is indicated by "?" at A, which occurs during
initial synchronization and when received signal is lost for an
extended period; unlock condition is indicated by other than " " at
Q
example: "216:15:36:43 "
D T Q
"<cr>hh:mm:ss.f dd/mm/yy<cr>"
C T A D
poll: none; offsets: T = 0, D = 15, A = 9, Q = none
hh:mm:ss = hours, minutes, seconds
f = deciseconds ("?" when out of spec)
dd/mm = day, month
yy = year (from DIPswitches)
note: 0?:??:??.? is displayed before synch is first established and
hh:mm:ss.? once synch is established and then lost again for about
a day
example: "15:36:43.6 04/08/91"
T A D
"ahh:mm:ss.fffs<cr>" "yy/dd/mm/ddd<cr>" "frdzycchhSSFTttttuuxx<cr>"
T C D A Q
poll: "QTQDQM"; offsets: T = 1, D = 24, Q = 41, A = 37
a = AM/PM indicator (" " for 24-hour mode)
hh:mm:ss.fff = hours, minutes, seconds, milliseconds
s = daylight-saving indicator (" " for 24-hour mode)
yy = year (from DIPswitches)
dd/mm/ddd = day of month, month, day of year
f = frequency enable (O = all frequencies enabled)
r = baud rate (3 = 1200, 6 = 9600)
d = features indicator (@ = month/day display enabled)
z = time zone (0 = UTC)
y = year (5 = 91)
cc = WWV propagation delay (52 = 22 ms)
hh = WWVH propagation delay (81 = 33 ms)
SS = status (80 or 82 = operating correctly)
F = current receive frequency (4 = 15 MHz)
T = transmitter (C = WWV, H = WWVH)
tttt = time since last update (0000 = minutes)
uu = flush character (03 = ^c)
xx = 94 (unknown) (firmware revision X4.01.999 only)
note: alarm condition is indicated by other than "8" at A, which
occurs during initial synchronization and when received signal is
lost for an extended periodunlock condition is indicated by other
than "0000" in the tttt subfield at Q
example: " 15:36:43.640 91/08/04/216 O3@055281824C00000394"