TERMINAL/FALLBACK
Enables or modifies TFF terminal parameters. The /FALLBACK qualifier
is required, but you can place it before or after the terminal-name
parameter.
SET TERMINAL/NOFALLBACK takes no options and is equivalent to SET
TERMINAL/FALLBACK=TABLE:NONE.
Format: SET TERMINAL /FALLBACK[=(Option,...)] [terminal_name]
SET TERMINAL/NOFALLBACK [terminal-name]
1 – Parameter
terminal-name
Indicates the target terminal for the set operation. If not
specified, your own terminal is used. Note that you can use TFF only
from local terminals; you cannot use terminal fallback on a remote
terminal (RTAx), the fallback terminal device (FBA0), a Packet
Switch Interface (PSI) terminal (NVA0), a disconnected virtual
terminal, or a terminal set for dynamic switching (DYNSWITCH) with
DECnet.
You can use TFF locally and then use the DCL command SET HOST to
access a remote system.
option
Modifies the terminal parameters. If you specify more than one,
enclose them in parentheses, and separate each with commas. You can
use the following options with the FALLBACK=option qualifier:
Option Definition
[NO]ACCEPT Enables input of 8-bit characters if the
terminal is capable of generating 8-bit
characters. The default is 7-bit character
generation. 7-bit terminals, such as VT1xx
and LA1xx, should have this feature turned
off whereas VT2xx terminals may have it on
(depending on the active table). The NOACCEPT
option causes TFF to clear the eighth bit.
[NO]AUTOCOMPOSE Enables or disables all auto-compose keys
available for the fallback table associated
with a terminal. The AUTOCOMPOSE and
NOAUTOCOMPOSE options override any keys
specified with the ENABLE and DISABLE options
described next.
DISABLE=(value[,...]) Disables one or more active auto-compose
keys. Keys are chosen from the list of keys
available for the fallback table associated
with a terminal. The value argument is a list
of the decimal values of the keys to disable.
If you specify more than one value, separate
the values with commas and place them in
parentheses. SHOW TERMINAL/FALLBACK lists the
currently active keys and their decimal
values.
ENABLE=(value[,...]) Enables one or more auto-compose keys. Choose
keys from the list of keys available for the
fallback table associated with the specified
terminal. The value argument is a list of the
decimal values of the keys to enable. If you
specify more than one value, separate the
values with commas and place them in
parentheses. SHOW TERMINAL/FALLBACK lists the
currently active keys and their decimal
values.
GX_DEFAULT:gx-name Defines as the default character set the name
of a character set, previously defined and
stored in Read Only Memory (ROM) of the
specified terminal. For example, VT100LD
specifies the line drawing alternate
character set available on VT100 terminals,
and DECSUPP specifies DIGITAL's supplemental
character set.
These options are available for a variety of
incompatible terminals. For example, the
ASCII option applies to a special class of
older DIGITAL terminals that do not have an
ASCII ROM that allows display of the full
ASCII character set. These terminals have
only the NRC set of characters.
Currently you can specify any of the
following character sets for the default:
ASCII, CANADA, CANADA_2, DECSUPP, FINLAND,
FINLAND_2, FRANCE, GERMANY, ITALY, JIS,
NETHERLAND, NORDAN, NORWAY, NORWAY_2, SPAIN,
SPECIAL1, SPECIAL2, SPECIAL3, SWEDEN,
SWEDEN_2, SWISS, TCS, UK, or VT100LD.
For more information about available default
and alternate ROM-based character sets, see
the documentation for your specific
terminal.
[NO]SIGNAL Enables the output of a BELL character to
sound a terminal bell when an invalid compose
sequence is entered. This is the default. You
can disable this feature for applications
that split escape sequences (for output) into
two or more QIOs, because the BELL character
may destroy such a sequence.
[NO]SOFT_COMPOSE Enables software emulated compose, using the
terminal's compose sequence validation table.
You can enter compose sequences either by
pressing CTRL/K followed by the sequence, or
by pressing an auto-compose key followed by
the second character of the sequence.
[NO]SUSPEND Suspends or resumes TFF intervention. In
command procedures that perform data
transfers over the terminal line, use the
SUSPEND option to avoid having to remember
which TFF parameters to be reset. The SUSPEND
option suspends TFF intervention until you
specify NOSUSPEND.
TABLE:table-name Indicates the name of the fallback table to
enable. If you omit the table-name option and
the terminal does not yet have fallback
enabled then the system default is used.
Otherwise, no change is made to the
terminal's table. Specify NONE for the table
to disable fallback for the target terminal.
This is equivalent to SET
TERMINAL/NOFALLBACK.
Before you can enable it, the target table
must be present in nonpaged dynamic memory
pool. Use the SHOW TABLES command for
information about what tables are available.
TERMINAL:terminal_type Specifies the terminal type, as seen by TFF.
The terminal type controls part of the escape
sequence parsing done by TFF. Thus, you
should set this to the correct value. Use one
of the following values: VT100, VT102, VT200,
or AL_ARABI. VT102 also includes the
terminals that are named VT100xy, such as
VT100WF.
2 – Examples
1. TFU> SET TERMINAL/FALLBACK=(ACCEPT, NOSIGNAL)
The command in this example enables fallback using system defaults,
if they are not already enabled. The option ACCEPT enables input of
8-bit characters; NOSIGNAL disables the terminal bell that sounds
when invalid compose sequences are entered.
2. TFU> SET TERMINAL/FALLBACK=(ACCEPT, TABLE:HANGUL_DS)
The command in this example enables fallback for the current
terminal, using the 16-bit character fallback table i.e. HANGUL_DS,
and input of 8-bit characters.
3. TFU> SET TERMINAL TXB0: /FALLBACK=TABLE:NONE
The command in this example disables fallback for terminal TXB0.
This is the same as SET TERMINAL/NOFALLBACK TXB0. Note that you can
place qualifiers before or after the terminal-name parameter.