IBM 3708 Description page 189

Color and Highlighting Restrictions
The 3708 supports highlighted fields and colors for terminals that provide this
function in character mode. These terminals must accept a SET ATTRIBUTE type
command for highlighting or color.
How the highlighting and color are supported depends on the value of bit 5 of the
Flag byte in the terminal table. If bit 5 is 0, the terminal must have the following
characteristic:
• The highlighting or color mode remains active for all subsequent characters
received by the terminal until another SET ATTRIBUTE command is received.
If bit 5 is 1, the terminal must have the following characteristics:
• The terminal reserves a byte on its screen for the attribute, but no character is
displayed there.
• The "current" attribute defines a field that extends to the "next" attribute.
If the "next" attribute is in the middle of a line, the current field wraps from
one line to the next.
If the "next" attribute is above the "current" attribute, the current field
wraps from the bottom of the screen to the top.
• The terminal does not do any cursor manipulation based on the location of the
attributes. That is, if the 3708 sends a command to move the cursor one
position to the left, the terminal performs that action, even if the new position
contains an attribute.
• The setting of bit 3 of the UDT Flag byte (SCROLL) must be zero. The 3708
must be able to send a character or attribute sequence to the last screen position.
As a result, a customer defining a UDT must determine. which of these sets of
requirements are satisfied by the terminal in question before defining the color or
highlighting outbound functions.
A possible symptom of an error in this area would be that the key tracking provided
by the 3708 (that is, cursor movement and so on) would appear to be wrong. For
example, when a cursor left key is pressed, the cursor might not actually move, or
when a TAB key is pressed, a blank may appear where data had already been
entered.
The 3708 restrictions in this area apply to the following default terminals:
• IBM 3101 - Highlighting is not provided by the 3101 in character mode.
• Beehive ATL078 - Originally, the 3708 did not support terminals with the second
set of characteristics above. Therefore, the default terminal table for this device
has bit 5 set to 0 and no highlighting sequences defined.
• Northern Telecom Displayphone - Originally, the 3708 did not support terminals
with the second set of characteristics above. Therefore, the default terminal
table for this device has bit 5 set to 0 and no highlighting sequences defined.
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IBM 3708
Description