Ultralink Clock


Table of Contents


Synopsis

Address: 127.127.34.u
Reference ID: WWVB
Driver ID: ULINK
Serial Port: /dev/wwvb_u_; 9600 bps, 8-bits, no parity
Features: (none)


Description

This driver supports the Ultralink Model 325 (replacement for Model 320) RS-232 powered WWVB receiver.

This driver also supports the Model 320, 330,331,332 decoders in both polled or continous time code mode.Leap second and quality are supported. Most of this code is originally from refclock_wwvb.c with thanks. Any mistakes are mine. Any improvements are welcome.


Model 325 timecode format

‹cr›‹lf›RQ_1C00LYYYY+DDDUTCS_HH:MM:SSL+5

Value Description
RQ Signal readability indicator, ranging from R1 to R5 where R1 is unreadable, R5 is best reception
_ Space
1 prev. received data bit, values: 0, 1, M, or ? unknown
C Signal reception from Colorado or Hawaii
00 Hours since last WWVB time and flag code update, values 00 to 99 (hopefully always 00)
L HEX A5 if receiver is locked to WWVB, Space if not
YYYY Year from 2000 to 2099
+ + if current year is a leap year, else ''
DDD current day in the year from 1 to 365/366
UTC timezone (always UTC)
S Daylight savings indicator
STD
DST
O transition into DST
I transition out of DST
HH UTC hour 0 to 23
: Time delimiter: : if synced, space if not
MM Minutes of current hour from 0 to 59
SS Seconds of current minute from 0 to 59
mm 10’s milliseconds of the current second from 00 to 99
L Leap second pending at end of month: Insert, Delete, or space
+5 UT1 correction in +/- .1 sec increments

Note that Model 325 reports a very similar output like Model 33X series. The driver for this clock is similar to Model 33X behavior. On a unmodified new ULM325 clock, the polling flag (flag1 =1) needs to be set.


Model 320 timecode format

‹cr›‹lf›SQRYYYYDDD+HH:MM:SS.mmLT‹cr›

Value Description
S S: sync’d in last hour
0-9: hours x 10 since last update
else ?
Q Number of correlating timeframes, from 0 to 5
R R: reception in progress
N: Noisy reception
'' standby mode
YYYY year from 1990 to 2089
DDD current day from 1 to 366
+ if current year is a leap year
HH UTC hour 0 to 23
MM Minutes of current hour from 0 to 59
SS Seconds of current minute from 0 to 59
mm 10’s milliseconds of the current second from 00 to 99
L Leap second pending at end of month
I: insert
D delete
T DST to STD transition indicators

Note that this driver does not do anything with the T flag. The M320 also has a U command which returns UT1 correction information. It is not used in this driver.


Model 33x timecode format

S9+D 00 YYYY+DDDUTCS HH:MM:SSl+5

Value Description
S sync indicator
S insync
N not in sync
the sync flag is WWVB decoder
sync has nothing to do with time being correct
9+ signal level 0 thru 9+
If over 9, indicated as 9
D data bit (fun to watch but useless), space
00 hours since last GOOD WWVB frame sync space
YYYY current year
+ leap year indicator
DDD day of year
UTC timezone (always UTC)
S daylight savings indicator space
HH hours : This is the REAL in sync indicator where : means insync)
MM minutes
: in sync
? NOT in sync
SS seconds
L leap second flag
+5 UT1 correction (sign + digit)

This driver ignores UT1 correction, DST indicator, Leap year, and signal level.


Fudge factors

flag1 polling enable (1=poll 0=no poll)