7-Bit Vs 8-Bit Operation - HP 262SA Reference Manual

Keyboards and Character Sets
able, the just entered character replaces the mute symbol as the displayed character, and the
cursor advances to the next position. The case may arise, however, when you want to enter just
the diacritic mark or accent character. Therefore, if you type a space after a mute symbol, the
mute symbol remains displayed and the cursor advances to the next character position.
7·Bit Vs a-Bit Operation
The terminal has two modes of operation that affect how characters received from datacomm
are interpreted by the terminal. The modes are named for the number of significant bits they
contain. In 8-bit mode all bits are significant; thus no bit is available for parity checking. In
7-bit mode, the seven low-order bits contain valid data. The eighth bit may be used for parity
checking, or it may be ignored.
7-BIT MODE. When the terminal is configured for 7-bit mode, the least significant seven bits
of the character byte determine the character's identity. That is, the seven bits are translated
into the appropriate character according to the installed character ROM for that keyboard
option. It is important to note that in 7-bit mode, the only accessible alphanumeric characters
are those available within a keyboard's base character set. For example, while in 7-bit mode, if
the terminal supports USASCII, the terminal only recognizes the standard 128 US ASCII
characters.
Table B-1 shows the replacement characters for each language selection based upon their
ASCII decimal value.
Table B-1. 7 Bit Code Substitutions
LANGUAGE KEYBOARD
DECIMAL VALUE
OPTION # 35 39 64 91 92 93 94 96 123 124 125 126
USASCII (standard)
#
,
@
[ \
]
"
C
{
I
} ........
SWEDISH 001 #
,
E A 0 A -0
e a
0
a
u
NORWEGIAN 002
#
,
@ IE 0
A
"
...
re
/J
a
..
GERMAN 004 £
,
§
A 0 -0
"
...
a
0
u
f3
UNITED KINGDOM 005 £
,
@ [ \
] "
...
{
I
} ........
SPANISH 006
#
,
@
i
N
i.,
0
...
{
Ii
}
..
FRCANADIAN 007
#
,
@
[
~
] "
... e
Q E
..
FRENCH 008 £
,
a
0
~
§
"
...
e
u
e
..
ITALIAN 009
£
,
§ 0
~
e
"
u a
0
e
i
DUTCH 010
#
,
@
~
\ § "
...
f
I
..
........
FINNISH 011
#
,
E A 0 A -0
e a
0
a
u
DANISH
012 §
,
@ IE
0
A
"
...
re
/J
a
..
NOTE: No correlation necessarily exists between the ASCII numerical values and the corres-
ponding position of keys upon the associated keyboards. For example, the ASCII
decimal value cC92" maps into the reverse slant (\) on the USASCII keyboard. On the
French keyboards, CC92" maps into c-cedilla ( ). However, the c-cedilla key on the
French keyboard does not physically correspond to the USASCII keyboard's reverse
slant key.
B-5