DEC VT220 Technical Manual page 164

Reserved
internal
7.5.6.3
for the
routines.
Code -- The number 7F (hexidecimal) is reserved
keyboard input and output buffers that handle
7.5.6.4 Test Mode The keyboard jumps into a test mode by
command during production test. The keyboard transmits a special
code to the system module to confirm the test mode. If the system
module receives this code, it should send the byte 80
(hexidecimal) to continue. This causes a jump to power up.
7.5.6.5
use as
codes.
7.5.7
Future Expansion -- Some keycodes are reserved for future
special codes or keycodes. Table 7-5 lists these reserved
Default Conditions
The LK201 has the following default conditions.
o Certain keyboard divisions have specific default modes.
Some divisions default to the autorepeat mode. Therefore,
they have an associated buffer that contains the default
values for timeout and interval. Timeout is the amount of
time that the keyboard waits before starting to
autorepeat a character. The rate of autorepeating a
character is called the interval. Table 7-5 shows the
defau t modes and Table 7-6 shows the default rates in
t four keyboard division autorepeat rate buffers.
o
The volume levels for the keyclick
eight-step range. The default volume
keyclick and bell are the third loudest.
and bell have an
levels for the
o For the LK201 keyboard, the CTRL (control) key defaults
to the no keyclick state.
7.5.7.1 Audio
decimals (010
keyboard (the
unless enabled
Bl1 (SHIFT keys
Volume Both keyclick and bell volumes are two
binary) by default. The key in position C99 of the
CTRL key in the LK201) does not generate a click
by the system module. The keys in
po~ition
B99 and
on the LK201) never generate a keyclick.
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