CDM-625 Advanced Satellite Modem
Revision 1
Front Panel Operation
MN-0000036 (Ref MN/CDM625.IOM)
5.1.2
Front Panel Keypad
IMPORTANT
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 digits, such as frequency or
data rate.
The function of the keypad is as follows:
ENTER
This key is used to select a displayed function or to execute a modem configuration change.
CLEAR
This key is used to back out of a selection or to cancel a configuration change which has not been
executed using [ENTER]. Pressing [CLEAR] generally returns the display to the previous selection.
◄
►
(Left,
Right)
These arrows are used to move to the next selection or to move the cursor functions. At times,
they may also used to move from one section to another.
▲
▼
(Up,
Down)
These arrows are used primarily to change configuration data (numbers). At times, they may
also be used to move from one section to another.
5.1.3 Front Panel Vacuum Fluorescent Display (VFD)
The CDM-625 features a
V
acuum
F
luorescent
D
isplay (VFD). The VFD
is an active display showing two lines
of 40 characters each. It produces a
blue light, the brightness of which can be controlled by the user. Compared to a
L
iquid
C
rystal
D
isplay (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 that activates after 1 hour:
The message moves from right to left across the screen, then wraps around. The top line of the
display shows the Circuit ID (which can be entered by the user). The bottom line shows the
circuit Eb/No value (if the demod is locked) followed by ‘
Press any key....’.
Pressing any key will restore the previous screen.
5–3
