Meinberg GPS LANTIME - Handbuch (Seite 9)

The Front Panel Layout
FAIL LED
The FAIL LED is turned on whenever the TIME_SYN output is low (receiver is not
synchronized).
LOCK LED
The LOCK LED is turned on when after power-up the receiver has acquired at least
four satellites and has computed its position. In normal operation the receiver position is
updated continuously as long as at least four satellites can be received. The LOCK LED
is blinking when the GPS has locked and the NTP is not synchronized
BSL Key
Whenever the on-board software must be upgraded or modified, the new firmware can
be downloaded to the internal flash memory via the serial port COM0. There is no need
to open the metal case and insert a new EPROM.
If the BSL key behind the front panel is pressed while the system is powered up, a
bootstrap-loader is active and waits for instructions from the serial port COM0. The
new firmware can be sent to GPS167SV from any standard PC with serial interface. A
loader program will be shipped together with the file containing the image of the new
firmware.
The contents of the program memory will not be modified until the loader program
has sent the command to erase the flash memory. So if the BSL key is pressed
unintentionally while the system is powered up, the firmware will not be changed
accidentally. After the next power-up, the system will be ready to operate again.
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