TrueTime 151-600, Manual

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X X L L D D C C M M A A N N . . d d o o c c 3 3 - - 1 1 R R E E V V E E
SECTION III
OPERATION AND KEYPAD FUNCTION
3-1 INTRODUCTION
The Model XL-DC Time and Frequency Receiver provides extremely accurate TIME and FREQUENCY
that is traceable to the UNITED STATES NAVAL OBSERVATORY (USNO) by use of the NAVSTAR
Global Positioning System (GPS). This section provides a complete description of the operation of the
XL-DC. For the Model XL-DC-600, all references to the front-panel keypad and displays should be
ignored as they are not available on that unit. For the Model XL-DC-601, all references to the large
numeric LCD time display should be ignored as it is not available on that unit.
3-2 GENERAL OPERATION
Every effort has been made to make the operation of the XL-DC backwardly compatible with the
Keypad and Serial I/O functionality of the GPS-DC and GPS-TMS/TMD products, however some
differences exist. The three most-used functions (TIME, STATUS and POSITION) have been assigned
to front-panel pushbuttons. All remaining functions may be accessed via the front-panel keypad and
viewed on a front-panel alphanumeric display or accessed via the Serial Port interface and viewed on a
monitor.
3-3 XL-DC START-UP
At power up, the unit will present messages on the small front panel display to indicate the version of
software installed in the unit, and how to invoke the keypad help function. The first message is the
version of the system software. For example:
TRUETIME Mk III
sys ver 020
After a few seconds, the display will show:
Press func, 0, 0
for help.
Then the display will show the version of the clock-specific software:
GPS-XL V1.036
182-6007v015
After a few seconds, the display will show the status display, which will remain until a keypad function is
invoked, or the "TIME" or "POSITION" button is pressed.
It should be noted that the text of the version messages will vary from model to model and version to
version.