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Author: David L. Mills (email@example.com)
Last update: 11-Sep-2010 05:56 UTC
Reference ID: WWV
Driver ID: WWV_PST
Serial Port: /dev/wwvu; 9600 baud, 8-bits, no parity
This driver supports the PSTI 1010 and Traconex 1020 WWV/WWVH Receivers. No specific claim of accuracy is made for these receiver, but actual experience suggests that 10 ms would be a conservative assumption.
The dipswitches should be set for 9600 bps line speed, 24-hour day-of-year format and UTC time zone. Automatic correction for DST should be disabled. It is very important that the year be set correctly in the DIP-switches; otherwise, the day of year will be incorrect after 28 April of a normal or leap year. As the there are only four dipswitches to set the year and the base value of zero correspondes to 1986, years beyond 2001 recycle with the value of zero corresponding to 2002. The propagation delay DIP-switches should be set according to the distance from the transmitter for both WWV and WWVH, as described in the instructions. While the delay can be set only to within 11 ms, the fudge time1 parameter can be used for vernier corrections.
Using the poll sequence QTQDQM, the response timecode is in three sections totalling 50 ASCII printing characters, as concatenated by the driver, in the following format:
ahh:mm:ss.fffs<cr> yy/dd/mm/ddd<cr> frdzycchhSSFTttttuuxx<cr> on-time = first <cr> hh:mm:ss.fff = hours, minutes, seconds, milliseconds a = AM/PM indicator (' ' for 24-hour mode) yy = year (from DIPswitches) dd/mm/ddd = day of month, month, day of year s = daylight-saving indicator (' ' for 24-hour mode) 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)
The alarm condition is indicated by other than 8 at a, which occurs during initial synchronization and when received signal is lost for an extended period; unlock condition is indicated by other than 0000 in the tttt subfield.
When enabled by the flag4 fudge flag, every received timecode is written as-is to the clockstats file.
Reference Clock Drivers