USNOTIME
DOCUMENTATION
6/1/87


USNOTIME.BAS IS A UTILITY TO LOAD THE EXACT TIME GENERATED BY THE U.S
NAVAL OBSERVATORY TIME CLOCK DIRECTLY INTO YOUR DOS CLOCK. THE PROGRAM
ACCESSES YOUR MODEM AND CALLS WASHINGTON, D.C. AT 202-653-0351. WHEN
THE USNO ANSWERS IT SPITS OUT REPETITIVELY THE DATE AND TIME. THIS
PROGRAM DOES NOT EXTRACT THE DATE. THE STRING USNO$ REFERRED TO IN THE
PROGRAM, COLLECTS THE DATA FROM USNO AND THEN ONLY THE LAST FEW BYTES
ARE IMPORTANT. A SAMPLE STRING MIGHT BE "46915 120 223427 UTC" FOLLOWED
BY A CR/LF AN ASTERISK AND ANOTHER CR/LF. THE 46915 CONTAINS THE
Modified Julian Date (MJD) WHICH IS FIGURED BY SUBTRACTING A CONSTANT
(2,400,000.5) FROM THE JULIAN DATE (NUMBER OF DAYS SINCE NOON
JANUARY 1, 4713 B.C.). THE 120 REPRESENTS THE DAY OF THE YEAR AND THE
223427 IS THE 22ND HOUR, 34TH MINUTE, 27TH SECOND. IF YOU REALLY WANT
ACCURACY THEN THE ASTERISK CAN BE USED TO DETERMINE THE TIME DELAY OVER THE
PHONE LINES IN MILLESONDS. THE DELAY CAN VARY BETWEEN 20-300 MILLISECONDS,
DEPENDING ON WHETHER THE CALL WAS LANDLINE OR SATELLITE. A HAYES COMPATIBLE
MODEM IS NEEDED FOR THIS PROGRAM, BUT YOU WILL SEE THE LINE INITIALIZING
THE MODEM, AND YOU CAN ADD WHATEVER COMMANDS YOU WANT OR NEED TO MAKE IT
WORK FOR YOUR MODEM. NOW, I ATTEMPTED TO COMPILE THIS THING, AT ABOUT 1:00AM
AND GOT MIXED RESULTS. SOMETIMES IT WORKED, OTHER TIMES I GOT RUN-TIME
ERRORS. I THINK IT HAS SOMETHING TO DO WITH THE READ/WRITE OF OPENING A
COM PORT, BUT I AM TIRED, AND THE COMPILED SIZE WAS JUST TOO BIG TO JUSTIFY
THIS LITTLE PROGRAM. I HEARD ABOUT THIS SERVICE USNO HAD, SO I THOUGHT
I WOULD TRY TO USE IT TO MY ADVANTAGE. AT LEAST MY TELEPHONE TESTING WAS
LATE AT NIGHT, THERFORE CHEAPER. NOTE: IF YOU HAVE A CLOCK CALENDAR CARD,
THAT WILL HAVE TO BE RESET, BY WHATEVER SOFTWARE CAME WITH IT. ONLY
THE DOS CLOCK GETS UPDATED. MY EXPERIENCE FROM CLOCK/CALENDAR BOARDS IS,
THAT YOU CAN NEVER GET THEM EXACTLY CORRECT.


BILL BOYER
13814D EAST LEHIGH AVE.
AURORA, CO 80014