[BC] Need clock for SX-5 w/ Sunwatch

[Dan Dickey]

I designed the Sunwatch along with George Stephenson (now deceased).  It was
the brainchild of Joe DeAngelo.  He pestered me for about 2 months that it
would be a good idea.  I think he was right.

The SLC-1 functionality can be easily duplicated by any old PC with a
working serial port and a little software.  The SLC-1 works by maintaining
an internal clock that actually runs off the power line frequency except
when that fails.  Then it runs on an internal battery.  This is much like a
PC internal clock.  Any old Windows or Linux box that uses time.nist.gov or
some other NNTP server to keep an accurate clock could be used.

The SLC-1 serial port was designed as an RS-232 robot.  It was mainly used
on old Digital Equipment systems to set the time for the computer when it
booted.  This was in the days before a UPS was reasonably priced.  Because
it was designed to act like the console operator during the boot process it
has a "wierd" way of working.  When the SLC-1 receives one of several
special strings, e.g. "DATE (M/D/Y) ?", it returns the information that the
boot program wanted by return serial strings.  The main issue is that the
trigger strings it is looking for were programmable.  It has been many years
since I worked on the Sunwatch and I don't remember the exact trigger
strings for date and time.  However, if anyone has a working unit all you
have to do is connect a PC serial cable to the SX transmitter and run
HyperTerminal.  I think the baud rate is 9600,N,8,1 or it might be
9600,E,7,1.  The SX will spit out the trigger string every so often and you
can see what it is.  Then just write a trivial C program that looks for that
string and sends the time and date strings back out the serial port just
like the SLC-1 did.  To find out what the SLC-1 time and date strings look
like just hook it up to HyperTerminal and type the trigger strings.  The
SLC-1 will happily respond with requested information.

If someone can get me the SLC-1 trigger strings and responses I could
probably whip up a program sometime next month but the program is way
trivial so I expect any number of people on this list could write it.  I'll
be happy to help if there is interest.

Best regards,
Dan Dickey