H Heuer Instruments UMDT51A User Manual page 19

Press and hold until the LT51 turns on. Press and release to turn
off. When the LT51 appears stuck on, press and hold the key
until LT51 turns off (~5s).
Clears currently displayed parameter entry box or message box.
If no box is displayed, save the current measurement to the
tester's non volatile memory
During parameter entry, moves cursor right to next digit or wraps
around if at end. If parameter entry is not active, displays current
volume setting for speaker, or in TDR mode, enables vertical or
horizontal zoom. Adjust by turning knob.
Turns the LCD back-light on or off.
Table 2-4. LT51 control keys
Table 2-5. Soft-keys
Table 2-6. Alphanumeric keys
LT51 User Manual
Five square numbered keys that are located directly
beside the LCD.
These are software-defined keys (called "soft-keys")
that carry out commands related to the currently
displayed screen. To locate the function of a key,
look on the LCD directly beside the key.
Provide a 12-key telephone pad so that you can
enter numbers, the asterisk (*), and pound sign (#).
In the correct context (such as entering a Save
string ID), alphabetic characters can be selected
using the multi-tap protocol for keys, widely used
when sending an SMS on a mobile phone. Eg. to
enter "debug1":

Press "3" once for 'd'

Wait 1s, then press "3" twice for 'e'

Press "2" twice for 'b'

Press "8" twice for 'u'

Press "4" once for 'g'

Press "1" repeatedly until '1' appears

Press OK to enter text
To select the 's' character, you would press the '7'
digit 4 times in quick succession. After a 1 second
delay the next character can be entered in a similar
way.
Controls and connections
7