60
Reference Monitors User Handbook
5
SERIAL INTERF
A
CE C
OMMANDS & RESPONSES
SERIAL INTERFACE
COMMANDS & RESPONSES
If using a terminal program, to achieve reliable data transfer the Line Delay (found under
File>Properties>Settings>ASCII Setup in Hyperteminal) should be set to 20ms.
It is vital that neither the serial connection nor mains power to the Reference Monitor
should be interrupted during the update process. If this should happen, or the update is
unsuccessful for any other reason, the Reference Monitor will not operate normally and will
instead enter a protected Bootloader mode. In this mode, the unit has a limited command
set and will await a successful retry of the update process.
Should the firmware update appear to succeed but the unit not behave as expected,
the update may be repeated either via the DWN: command (if the unit will respond to
commands) or, in extreme circumstances, by setting switch number 12 in Block 1 of
configuration switches (found on the underside of the unit) to ON. This action will force
the Bootloader to run and allow initiation of an update under any circumstances. After
completion of the update, the switch should be returned to the OFF position.