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MBT-5003 L-Band Up/Down Converter System
Front Panel Operation
5.1.3
Keypad
(Up, Down)
(Left, Right)
The keypad has an auto-repeat feature. If a key is held down for more than 1
second, the key action will repeat, automatically, at the rate of 15 keystrokes
per second. This is particularly useful when editing numeric fields, with many
IMPORTANT
digits, such as frequency or data rate.
5.1.4
Vacuum Fluorescent Display (VFD)
can be controlled by the user. Compared to a Liquid Crystal Display (LCD), it has greatly
superior viewing characteristics and does not suffer problems of viewing angle or contrast.
On most menu screens, the user will observe a flashing solid block cursor, which blinks at a once-
per-second rate. This indicates the currently selected item, digit, or field. Where this solid block
cursor would obscure the item being edited (e.g., a numeric field) the cursor will automatically
change to an underline cursor.
If the user were to display the same screen for weeks at a time, the display could become 'burnt'
with this image. To prevent this, the unit has a 'screen saver' feature, which will activate after a
few minutes. The top line of the VFD will display the Circuit ID, and the bottom line will display
'Press any key...'. The message moves from right to left across the screen, then wraps
around. Pressing any key will restore the previous screen.
The keypad comprises six individual key switches. They have a
positive 'click' action, which provides tactile feedback. The
function of the front panel keypad is as follows:
The ENT (ENTER) key is used to select a displayed function or to execute a
modem configuration change.
The CLR (CLEAR) key is used to back out of a selection or to cancel a
configuration change which has not been executed using ENT. Pressing CLR
generally returns the display to the previous selection.
These arrows are used primarily to change configuration data (numbers), at the
current cursor position. Occasionally, they may be used to scroll through a
number of choices at the current cursor position. Most of the menus (space
permitting) include arrow key hints to guide the user.
These arrows are used to move to the next selection or to move the cursor
position. Most of the menus (space permitting) include arrow key hints to guide
the user.
The MBT-5003 features a Vacuum Fluorescent
Display (VFD). The VFD is an active display
showing two lines of 24 characters each. It
produces a blue light, the brightness of which
5–3
Revision 1
MN-MBT5003
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