chapter1.html

VT100向导

turn the built-in terminal features on or off. Instead, the VT100 uses a nonvolatile
memory (NVR) which always remembers what features have been selected, as if a
switch had been set.</P>
<P>The selection and storage of built-in terminal features is performed in a special
mode of operation called SET-UP mode. When you enter SET-UP mode, the status
of the features stored in the temporary memory is shown on the screen. You can
then change the features and store any new feature selections either temporarily,
by leaving SET-UP mode; or on a fixed basis, by performing a Save operation. In
either case, the terminal operation will reflect the new feature selection. If a recall
operation is performed, or the terminal is reset, or the terminal power is turned
OFF, all temporary feature settings are replaced by the features that have been
stored on a fixed basis.</P>
<H3 ID="S1.2.1">SET-UP Features at a Glance</H3>
<P>When entered, SET-UP mode provides two brief summaries of the current feature
status. The first presentation -- SET-UP&nbsp;A -- displays the location of the tab stops
set in the terminal and a visual ruler which numbers each character position on the
line. The second presentation -- SET-UP&nbsp;B -- summarizes the status of the other
terminal features.</P>
<P><STRONG>SET-UP&nbsp;A</STRONG> -- To enter SET-UP&nbsp;A, press the <SPAN CLASS="keyname">SET-UP</SPAN> key. The display will now have
a presentation similar to <A HREF="figure1-4.html">Figure&nbsp;1-4</A>. The bottom line of the display consists of a
"ruler" which numbers each character position available on a line. The location of
each tab stop is shown by a "T" placed above the ruler. If the tab stop(s) set are
those desired, you may exit SET-UP mode by pressing the <SPAN CLASS="keyname">SET-UP</SPAN> key again or
you may now change the tabs to meet your requirements.</P>
<P><STRONG>SET-UP&nbsp;B</STRONG> -- SET-UP&nbsp;B mode may only be entered from SET-UP&nbsp;A mode. To enter
SET-UP&nbsp;B from SET-UP&nbsp;A, press the <SPAN CLASS="keyname">5</SPAN> key on the main keyboard. The display will
then look like <A HREF="figure1-5.html">Figure&nbsp;1-5</A>.</P>
<P><A HREF="figure1-6.html">Figure&nbsp;1-6</A> summarizes the SET-UP&nbsp;B presentation. This summary allows you to
quickly determine what features are enabled. For additional information on a feature
refer to the Definition of Each Feature section.</P>
<P>To exit SET-UP&nbsp;B press the <SPAN CLASS="keyname">SET-UP</SPAN> key.</P>
<H3 ID="S1.2.2">Determining What a SET-UP Feature Does</H3>
<P>The SET-UP features are basically a series of options in the VT100 that allow the
terminal to be tailored to its operating environment. <A HREF="table1-1.html">Table&nbsp;1-1</A> lists each feature
and places it in one or more of the following general categories:</P>
<UL>
<LI>Installation</LI>
<LI>Computer compatibility</LI>
<LI>Operator comfort</LI>
</UL>
<P>The installation category concerns itself with the initial installation of the terminal
and any special options that may be attached to the terminal. If any terminal
options are added or removed, or the physical location of the installation is
changed, verify the settings of these SET-UP features.</P>
<P>Computer compatibility contains the features which must be set correctly so that
the VT100 can communicate with the host computer. An error in these settings
may cause incorrect data to be sent to or received from the computer; or an error
may prevent the VT100 from communicating with the computer. The settings for
these features must be obtained from the host computer programmer, operator, or
system manager since there are many combinations of settings designed to work
with particular computers and special software. These feature settings would normally
change only when you need to communicate with a different computer or a
unique software package.</P>
<P>The operator comfort category contains the SET-UP features designed exclusively
for the operator. These features allow the operator to tailor the VT100 to fit individual
preference. These features do not affect any operations that occur between
the terminal and the compuer.</P>
<P>The next section, Definition of Each SET-UP Feature, describes the specific function
of each feature.</P>
<H3 ID="S1.2.3">How To Change a SET-UP Feature</H3>
<P>Changing any or all of the SET-UP features is a simple operation and is generally
performed by following the same basic steps.</P>
<OL>
<LI>Enter SET-UP mode by pressing the <SPAN CLASS="keyname">SET-UP</SPAN> key</LI>
<LI>Select the appropriate SET-UP mode by pressing the <SPAN CLASS="keyname">5</SPAN> key on the main
keyboard each time you want to switch from SET-UP&nbsp;A to SET-UP&nbsp;B or
from SET-UP&nbsp;B to SET-UP&nbsp;A.</LI>
<LI>Position the cursor above the feature switch or tab stop to be changed.
To position the cursor, the <SPAN CLASS="keyname">SPACEBAR</SPAN>, <IMG SRC="keys/br/leftsmall.png" ALT="[Left]" HEIGHT="15" WIDTH="15">, <IMG SRC="keys/br/rightsmall.png" ALT="[Right]" HEIGHT="15" WIDTH="15">, <SPAN CLASS="keyname">TAB</SPAN> and <SPAN CLASS="keyname">RETURN</SPAN>
keys may be used. Some features do not use this step since a specific
key is dedicated to changing the feature.</LI>
<LI>Change the feature setting by pressing either the <SPAN CLASS="keyname">6</SPAN> key on the main
keyboard or the appropriate dedicated key. Each time the key is pressed
the feature will change, generally to the opposite state.</LI>
</OL>
<P><A HREF="table1-2.html">Table&nbsp;1-2</A> briefly summarizes the SET-UP features, the SET-UP mode you must be
in to change a given feature, and the key used to change the feature setting.</P>
<H3 ID="S1.2.4">Setting the Answerback Message</H3>
<P>Setting the answerback message is different from setting any of the other terminal
features. An answerback message can be typed into the VT100, using the following
steps:</P>
<OL>
<LI>Place the terminal in SET-UP&nbsp;B mode.</LI>
<LI>Press the <SPAN CLASS="keyname">SHIFT</SPAN> and <SPAN CLASS="keyname">A</SPAN> key simultaneously. The terminal will respond
by placing A&nbsp;= on the screen. (The <SPAN CLASS="keyname">SHIFT</SPAN> key is required. The
<SPAN CLASS="keyname">CAPS&nbsp;LOCK</SPAN> key will not work here.)</LI>
<LI>Type the message delimiter character which may be any character not
used in the actual answerback mesage. The message delimiter character
is not a part of the answerback message. If a mistake is made when
typing the answerback message, type the message delimiter character
again and go back to step 2. This is the <EM>only</EM> way to correct errors in the
answerback message.</LI>
<LI>Type the answerback message. The message may be up to 20 characters,
including space and control characters. Control characters will be
displayed as a <IMG SRC="diamondsmall.png" ALT="diamond" HEIGHT="15" WIDTH="12"> character to indicate their presence in the message.</LI>
<LI>Type the message delimiter character. Once the message delimiter
character is typed the answerback message will disappear from the
screen.</LI>
</OL>
<P>Once the above steps have been completed the answerback message will be temporarily
stored in the VT100 and can be saved with the Save operation.</P>
<H3 ID="S1.2.5">Saving the SET-UP Features</H3>
<P>SET-UP features may be changed and stored on either a temporary or a fixed
basis. To temporarily store a feature, exit SET-UP mode after changing the feature;
the terminal now reacts according to the new setting. If a recall operation is performed,
or the terminal is reset, or the terminal power is turned off, all temporary
feature settings are replaced by the features that have been stored on a fixed basis.</P>
<P>To store SET-UP feature settings on a fixed basis, perform a save operation. This is
a simple operation that is accomplished by performing the following steps:</P>
<OL>
<LI>Place the terminal in SET-UP mode.</LI>
<LI>Press the <SPAN CLASS="keyname">SHIFT</SPAN> and <SPAN CLASS="keyname">S</SPAN> keys simultaneously. The screen will clear and
the message "wait" will be displayed in the upper-left corner. After a
brief wait, the terminal will return to SET-UP&nbsp;A mode.</LI>
</OL>
<P CLASS="note">NOTE: The save operation must be performed at the terminal keyboard. The
computer cannot perform this operation, although it can temporarily modify the settings of
some VT100 features.</P>
<P>Once these steps have been performed, SET-UP features which had been temporarily
stored will now be stored on a fixed basis.</P>
<H3 ID="S1.2.6">Recalling SET-UP Features</H3>
<P>The temporarily stored SET-UP feature settings may differ from the settings which
have been stored on a fixed basis. If you wish to return to the fixed settings,
perform the recall operation as follows:</P>
<OL>
<LI>Place the terminal in SET-UP mode.</LI>
<LI>Press the <SPAN CLASS="keyname">SHIFT</SPAN> and <SPAN CLASS="keyname">R</SPAN> keys simultaneously. The screen will clear and
the message "wait" will appear in the upper-left corner of the screen.
After a brief wait the terminal will return to SET-UP&nbsp;A mode.</LI>
</OL>
<P CLASS="note">NOTE: When a recall operation is performed the contents of the
screen are destroyed.</P>
<H3 ID="S1.2.7">Resetting the Terminal</H3>
<P>The VT100 may be reset from the keyboard. When the terminal is reset, the terminal
memory is cleared and the self-test program is run as if the terminal power
switch had been turned OFF and then back ON. To reset the terminal:</P>
<OL>
<LI>Place the terminal in SET-UP mode.</LI>
<LI>Press the <SPAN CLASS="keyname">0</SPAN> key on the main keyboard. The VT100 will be reset, the
power on self-test will be run, and the terminal will set according to the
fixed SET-UP features.</LI>
</OL>
<P CLASS="note">NOTE: When a reset operation is performed the contents of the screen are
destroyed and any options present may be affected.</P>
<H2 ID="S1.3">Part 3 -- Definition of Each SET-UP Feature</H2>
<P>This section describes each SET-UP feature in detail (in alphabetical order) and
states how each feature affects the terminal.</P>
<P CLASS="note">NOTE: Unless otherwise stated, entering SET-UP mode and changing features
does not result in the loss of data displayed on the screen.</P>
<P><STRONG>ANSI/VT52 Mode</STRONG><BR>
The VT100 terminal follows two different programming standards -- American
National Standards Institute (ANSI) and VT52. In ANSI mode, the VT100 will
generate and respond to coded sequences per ANSI standards X3.41-1974 and
X3.64-1977. In VT52 mode, the VT100 terminal is compatible with previous
DIGITAL software using the VT52 video terminal. Both ANSI and VT52 modes are
outlined in the programmer's section of this manual.</P>
<P><STRONG>ANSWERBACK Message</STRONG><BR>
Answerback is a question and answer sequence where the host computer asks the
terminal to identify itself. The VT100 answerback features provides the terminal
with the capability to identify itself by sending a message to the host. The entire
answerback sequence takes place automatically without affecting the screen or
requiring operator action. The answerback message may also be transmitted by
typing <SPAN CLASS="keyname">CTRL</SPAN>-<SPAN CLASS="keyname">BREAK</SPAN>.</P>
<P><STRONG>AUTO REPEAT</STRONG><BR>
The auto repeat feature allows a key to be automatically repeated at the rate of
about 30 characters per second when the key is held down for more than one-half
second. The auto repeat feature affects all keyboard keys except the following:</P>
<UL>
<LI><SPAN CLASS="keyname">SET-UP</SPAN></LI>
<LI><SPAN CLASS="keyname">ESC</SPAN></LI>
<LI><SPAN CLASS="keyname">NO SCROLL</SPAN></LI>
<LI><SPAN CLASS="keyname">TAB</SPAN></LI>
<LI><SPAN CLASS="keyname">RETURN</SPAN></LI>
<LI><SPAN CLASS="keyname">CTRL</SPAN> and any key</LI>
</UL>
<P><STRONG>AUTO XON/XOFF</STRONG><BR>
The VT100 is capable of automatically generating synchronizing codes XON (DC1)
and XOFF (DC3). The XOFF code is used to stop the transmission of data from the
computer to the terminal; the XON code is used to resume transmission. With the
feature enabled, the VT100 will generate the XOFF code when one of the following
events occur:</P>
<OL>
<LI>The internal buffer is nearly full</LI>
<LI>The <SPAN CLASS="keyname">NO&nbsp;SCROLL</SPAN> key is pressed</LI>
<LI>The terminal is placed in SET-UP mode</LI>
<LI><SPAN CLASS="keyname">CTRL</SPAN>-<SPAN CLASS="keyname">S</SPAN> is pressed.</LI>
</OL>
<P CLASS="note">NOTE: The VT100 will always stop transmission when an XOFF (DC3) code