VT102 User Guide| Appendix C | +Contents | +Appendix E | +
This appendix summarizes the ANSI code extension techniques defined in +standards X3.41-1974 and X3.64-1979. Those specifications cover many +special cases and details not included here.
+The ANSI standards define types of characters used for specific purposes. +You can determine a character's type by its position in the ASCII +table (Table D-1). There are two general categories of characters:
+This table and the ANSI system can work for either a 7-bit or 8-bit character +environment. The VT102 uses only 7-bit characters.
+NOTE: The ASCII 7-bit table corresponds to International Standards Organization +(ISO) standard 646 and International Telegraph and Telephone +Consultive Committee (CCITT) alphabet 5.
+All control characters and groups of characters (sequences) not intended +for display on the screen are control functions. Not all control functions +perform an action in every ANSI device, but each device can recognize all +control functions and discard any that do not apply to it. Therefore, each +device performs a subset of the ANSI functions.
+Because different devices use different subsets, compliance with ANSI +does not mean compatibility between devices. Compliance only means +that a particular function, if defined in the ANSI standard, is invoked by the +same control function in all devices. If an ANSI device does not perform +an action that has a control function defined in the ANSI standard, it cannot +use that control function for any other purpose.
+Escape and control sequences provide more controls in addition to the +control characters in the ASCII 7-bit table. These multiple-character control +sequences are not displayed but control the displaying, processing, +and transmission of characters. At the end of a sequence or during an +error condition, the terminal continues to display received characters. +See Error Recovery in Chapter 5 for specific error conditions.
+The format for an escape sequence is as follows.
+ESC I.....I F +033 040-057 060-176 + +Escape Intermediate Final +sequence characters character +introducer (0 or more (1 character) + characters)+
This is the ESC character (octal 033) defined +by ANSI X3.4-1977. After receiving ESC, the terminal stores (but +does not display) all control characters received in the proper range.
These are characters received after ESC in +the octal range of 040 - 057 (column 2 of the ASCII table). The terminal +stores intermediate characters as part of the control function.
This is a character received after ESC in the octal +range of 060 - 176 (columns 3 - 7 of the ASCII table). The final character +indicates the end of the control function. The intermediate and final characters +together define the function of the sequence. The terminal then +performs the specified function and continues to display received characters. +ANSI standard control functions have a final character in the octal +range of 100 - 176 (columns 4 - 7 of the ASCII table). Private sequences +have a final character in the octal range of 060 - 077 (column 3 of the +ASCII table).
Action: Designate ASCII character set as G0.
+ESC ( B +033 050 102 + | | | + | | +------- Final Character + | +------------ Intermediate Character + +----------------- Escape Sequence Introducer+
The format of a control sequence is as follows.
+CSI P.....P I.....I F +033 133 060-077 040-057 100-176 + +Control Parameter Intermediate Final character +sequence characters characters (1 character) +introducer (0 or more (0 or more + characters) characters)+
The CSI is the ESC (octal 033) and [ (octal +133) characters defined by ANSI X3.41-1977. These characters provide +8-bit control functions by using 7-bit characters. The VT102 supports +only 7-bit characters. After receiving CSI characters, the terminal stores +(but does not display) all control characters received in the proper range.
These are characters received after the CSI +character, in the octal range of 060 - 077 (column 3 of the ASCII table). +The parameter characters modify the action or interpretation of the control +function. The terminal interprets parameter characters as private +when the < = > ? characters (octal 074 - 077) begin the paramter +string. The : character (octal 072) is reserved. This means an ANSI-specified +control sequence can have a parameter function with a private interpretation.
+The terminal uses two types of parameter characters, numeric and selective. +A numeric parameter represents a decimal number, designated by +Pn. The decimal characters have a range of 0 - 9 (octal 060 - 071). A +selective parameter comes from a list of specified parameters, designated +by Ps.
+If a control sequence includes more than one parameter, the parameters +are separated by a delimiter, the ; character (octal 073).
These are characters received after the CSI +character, in the octal range of 040 - 057 (column 2 of the ASCII table). +The terminal stores these characters as part of the control function.
+NOTE: The terminal does not use intermediate characters in control +functions.
This is a character received after the CSI character, in +the octal range of 100 - 176 (columns 4 - 7 of the ASCII table). The final +character indicates the end of the control function. The intermediate and +final characters together define the function of the sequence. The terminal +then performs the specified function and continues to display received +characters. ANSI standard control functions have a final character in the +octal range of 100 - 157 (columns 4 - 6 of the ASCII table). Private sequences +have a final character in the octal range of 160 - 176 (column 7 +of the ASCII table).
Action: Clear all horizontal tabs.
+ESC [ 3 g +033 133 063 147 + | | | | + +--+-+ | | + | | +----- Final Character + | +---------- Parameter Character + +----------------- Control Sequence Introducer+
These examples show the use of multiple functions selected in one sequence, +private parameters and private sequences.
+ESC [ ? 4 h Set smooth scroll mode +033 133 077 064 150 (? = ANSI private parameter) + +ESC [ 2 ; 1 y Invoke self-test +033 133 062 073 061 171 (y = ANSI private sequence)+ + + -- cgit v1.2.3