Data Link Layer
This section describes the data link layer.
9.3.1 7- /8-Bit VT100/VT520 Operation
The VT520 supports three broad classes of application requirements:
• Strict compatibility for existing VT100 applications:
– No 8-bit control codes
– No 8-bit data Function keys are not limited to the VT100 set as in
previous terminals.
• A migration path that allows most applications to run without modification:
– No 8-bit control codes
– 8-bit graphic data allowable
– VT400 function keys are allowable (but not immediately useful) and can
be integrated into the application over time.
• Full VT520 mode (VT level 5) functionality:
– 8-bit data allowable
– 8-bit controls allowable
– All VT500 function and modifier keys
The VT520 application requirements are possible through the following VT
terminal modes:
• VT52 Mode (7-bit characters, 7-bit controls)
• VT100 Mode (7-bit characters, 7-bit controls)
• VT500 Mode, 8-bit characters, 7-bit controls
• VT500 Mode, 8-bit characters, 8-bit controls
• VT500 Mode, 7-bit characters (Keyboard restricted to keys that generate 7-bit
codes, 7-bit graphics, 7-bit controls, for NRC sets, worldwide version only).
These modes are the only supported modes. 8-bit characters are temporarily
disabled when in VT100 mode.
The following are certain limitations within these modes:
• The terminal accepts both C0 and C1 controls when 8-bit characters are
selected (7-bit NRCS Characters is not selected).
• The terminal accepts both GL and GR characters when 8-bit Characters are
selected.
• In VT52 mode, VT100 mode, or VT500 mode, when 7-bit characters is
selected, the terminal sets the high bit of all received characters to zero. This
action results in compatible character handling. The received characters,
therefore, have only seven significant bits. This is applicable to both graphics
characters and control characters.
Es la información que me da el manual técnico
Lo que necesito es sustituir éste terminal, mañana tendré información de la tarjeta que le envía la información al terminal.