C Programming Summary

General

This appendix provides a summary of VT102 escape and control sequences.

Figure C-1 shows the codes generated by the standard keys. Figure C-2 shows the control codes generated by the function keys; shaded keys do not need CTRL down to generate the control character.

Programming Sequences

The rest of this appendix repeats the information on the VT102 Programming Reference Card (EK-VT102-RC-001).

Control Characters Received

Name	Character Mnemonic	Octal Code	Function
Null	NUL	000	Ignored when received (not stored in input buffer) and used as a fill character.
End of text	ETX	003	Can be selected as a half-duplex turnaround character.
End of transmission	EOT	004	Can be selected as a disconnect character or half-duplex turnaround character. When used as a turnaround character, the disconnect character is DLE-EOT.
Enquire	ENQ	005	Transmits answerback message.
Bell	BEL	007	Generates bell tone.
Backspace	BS	010	Moves cursor to the left one character position; if cursor is at left margin, no action occurs.
Horizontal tab	HT	011	Moves cursor to next tab stop, or to right margin if there are no more tab stops.
Linefeed	LF	012	Causes a linefeed or a new line operation. (See Linefeed/New Line mode). Also causes printing if auto print operation selected.
Vertical tab	VT	013	Processed as LF.
Form feed	FF	014	Processed as LF. FF can also be selected as a half-duplex turnaround character.
Carriage return	CR	015	Moves cursor to left margin on current line. CR can also be selected as a half-duplex turnaround character.
Shift out	SO	016	Selects G1 character set designated by a select character set sequence.
Shift in	SI	017	Selects G0 character set designated by a select character set sequence.
Device control 1	DC1	021	Processed as XON. DC1 causes terminal to continue transmitting characters.
Device control 3	DC3	023	Processed as XOFF. DC3 causes terminal to stop transmitting all characters except XOFF and XON. DC3 can also be selected as a half-duplex turnaround character.
Cancel	CAN	030	If received during an escape or control sequence, cancels the sequence and displays substitution character ().
Substitute	SUB	032	Processed as CAN.
Escape	ESC	033	Processed as a sequence introducer.

ANSI Compatible Sequences

Set Mode

Name	Mnemonic	Mode	Sequence
Keyboard action	KAM	Locked	`ESC [ 2 h`
Insertion-replacement	IRM	Insert	`ESC [ 4 h`
Send-receive	SRM	Off	`ESC [ 1 2 h`
Linefeed/new line	LMN	New line	`ESC [ 2 0 h`
Cursor key	DECCKM	Application	`ESC [ ? 1 h`
ANSI/VT52	DECANM	ANSI	N/A
Column	DECCOLM	132 column	`ESC [ ? 3 h`
Scrolling	DECSCLM	Smooth	`ESC [ ? 4 h`
Screen	DECSCNM	Reverse	`ESC [ ? 5 h`
Origin	DECOM	Relative	`ESC [ ? 6 h`
Auto wrap	DECAWM	On	`ESC [ ? 7 h`
Auto repeat	DECARM	On	`ESC [ ? 8 h`
Print form feed	DECPFF	On	`ESC [ ? 1 8 h`
Print extent	DECPEX	Full screen	`ESC [ ? 1 9 h`

Reset Mode

Name	Mnemonic	Mode	Sequence*
Keyboard action	KAM	Unlocked	`ESC [ 2 l`
Insertion-replacement	IRM	Replace	`ESC [ 4 l`
Send-receive	SRM	On	`ESC [ 1 2 l`
Linefeed/new line	LMN	Linefeed	`ESC [ 2 0 l`
Cursor key	DECCKM	Cursor	`ESC [ ? 1 l`
ANSI/VT52	DECANM	VT52	`ESC [ ? 2 l`
Column	DECCOLM	80 column	`ESC [ ? 3 l`
Scrolling	DECSCLM	Jump	`ESC [ ? 4 l`
Screen	DECSCNM	Normal	`ESC [ ? 5 l`
Origin	DECOM	Absolute	`ESC [ ? 6 l`
Auto wrap	DECAWM	Off	`ESC [ ? 7 l`
Auto repeat	DECARM	Off	`ESC [ ? 8 l`
Print form feed	DECPFF	Off	`ESC [ ? 1 8 l`
Print extent	DECPEX	Scrolling region	`ESC [ ? 1 9 l`
* The last character of the sequence is lowercase L (154₈)

Cursor Key Codes Generated

Cursor Key (Arrow)	ANSI Characters Generated
Cursor Key (Arrow)	Reset (Cursor)	Set (Application)
Up	`ESC [ A`	`ESC O A`
Down	`ESC [ B`	`ESC O B`
Right	`ESC [ C`	`ESC O C`
Left	`ESC [ D`	`ESC O D`

Keypad Character Selection

Name	Mnemonic	Sequence
Alternate	DECKPAM	`ESC =`
Numeric	DECKPNM	`ESC >`

Keypad Codes Generated

Key	VT52 Numeric Keypad Mode	VT52 Alternate Keypad Mode	ANSI Numeric Keypad Mode	ANSI Alternate Keypad Mode
0	0	`ESC ? p`	0	`ESC O p`

1	1	`ESC ? q`	1	`ESC O q`
2	2	`ESC ? r`	2	`ESC O r`
3	3	`ESC ? s`	3	`ESC O s`
4	4	`ESC ? t`	4	`ESC O t`
5	5	`ESC ? u`	5	`ESC O u`
6	6	`ESC ? v`	6	`ESC O v`
7	7	`ESC ? w`	7	`ESC O w`
8	8	`ESC ? x`	8	`ESC O x`
9	9	`ESC ? y`	9	`ESC O y`
- (minus)	- (minus)	`ESC ? m`	- (minus)	`ESC O m`
, (comma)	, (comma)	`ESC ? l`*	, (comma)	`ESC O l`*
. (period)	. (period)	`ESC ? n`	. (period)	`ESC O n`
ENTER	Same as RETURN	`ESC ? M`	Same as RETURN	`ESC O M`
PF1	`ESC P`	`ESC P`	`ESC O P`	`ESC O P`
PF2	`ESC Q`	`ESC Q`	`ESC O Q`	`ESC O Q`
PF3	`ESC R`	`ESC R`	`ESC O R`	`ESC O R`
PF4	`ESC S`	`ESC S`	`ESC O S`	`ESC O S`
* The last character of the sequence is lowercase L (154₈)

Select Character Sets SCS

Character Set	G0 Designator	G1 Designator
United Kingdom (UK)	`ESC ( A`	`ESC ) A`
United States (US)	`ESC ( B`	`ESC ) B`
Special characters and line drawing set	`ESC ( 0`	`ESC ) 0`
Alternate character ROM	`ESC ( 1`	`ESC ) 1`
Alternate character ROM - special characters	`ESC ( 2`	`ESC ) 2`

Name	Mnemonic	Sequence
Single shift 2	SS2	`ESC N`
Single shift 3	SS3	`ESC O`

Character Attributes

Name	Mnemonic	Sequence
Select graphic rendition (no attributes)	SGR	`ESC [ m`
Select graphic rendition (no attributes)	SGR	`ESC [ 0 m`
Select graphic rendition (select attribute bold)	SGR	`ESC [ 1 m`
Select graphic rendition (select attribute underline)	SGR	`ESC [ 4 m`
Select graphic rendition (select attribute blink)	SGR	`ESC [ 5 m`
Select graphic rendition (select attribute, reverse video)	SGR	`ESC [ 7 m`

Scrolling Region

Name	Mnemonic	Sequence
Set top and bottom margins	DECSTBM	`ESC [ Pt ; Pb r`

Cursor Movement Commands

Name	Mnemonic	Sequence
Cursor up	CUU	`ESC [ Pn A`
Cursor down	CUD	`ESC [ Pn B`
Cursor forward (right)	CUF	`ESC [ Pn C`
Cursor backward (left)	CUB	`ESC [ Pn D`
Cursor position	CUP	`ESC [ Pl ; Pc H`
Cursor position (home)	CUP	`ESC [ H`
Horizontal and vertical position	HVP	`ESC [ Pl ; Pc f`
Horizontal and vertical position (home)	HVP	`ESC [ f`
Index	IND	`ESC D`
Reverse index	RI	`ESC M`
Next line	NEL	`ESC E`
Save cursor (and attributes)	DECSC	`ESC 7`
Restore cursor (and attributes)	DECRC	`ESC 8`

Tab Stops

Name	Mnemonic	Sequence
Horizontal tab set (at current column)	HTS	`ESC H`
Tabulation clear (at current column)	TBC	`ESC [ g`
Tabulation clear (at current column)	TBC	`ESC [ 0 g`
Tabulation clear (all tabs)	TBC	`ESC [ 3 g`

Line Attributes

Name	Mnemonic	Sequence
Double-height top half	DECDHL	`ESC # 3`
Double-height bottom half	DECDHL	`ESC # 4`
Single-width single-height	DECSWL	`ESC # 5`
Double-width single-height	DECDWL	`ESC # 6`

Erasing

Name	Mnemonic	Sequence
Erase in line (cursor to end of line)	EL	`ESC [ K`
Erase in line (cursor to end of line)	EL	`ESC [ 0 K`
Erase in line (beginning of line to cursor)	EL	`ESC [ 1 K`
Erase in line (entire line containing cursor)	EL	`ESC [ 2 K`
Erase in display (cursor to end of screen)	ED	`ESC [ J`
Erase in display (cursor to end of screen)	ED	`ESC [ 0 J`
Erase in display (beginning of screen to cursor)	ED	`ESC [ 1 J`
Erase in display (entire screen)	ED	`ESC [ 2 J`

Editing Functions

Name	Mnemonic	Sequence
Delete character	DCH	`ESC [ Pn P`
Insert line	IL	`ESC [ Pn L`
Delete line	DL	`ESC [ Pn M`

Print Commands

Name	Mnemonic	Sequence
Media copy (enter auto print)	MC	`ESC [ ? 5 i`
Media copy (exit auto print)	MC	`ESC [ ? 4 i`
Media copy (enter printer controller)	MC	`ESC [ 5 i`
Media copy (exit printer controller)	MC	`ESC [ 4 i`
Media copy (print screen)	MC	`ESC [ i`
Media copy (print screen)	MC	`ESC [ 0 i`
Media copy (print cursor line)	MC	`ESC [ ? 1 i`

Reports

Name	Mnemonic	Sequence
Device status report (request status of VT102)	DSR	`ESC [ 5 n`
Response:
Terminal OK	DSR	`ESC [ 0 n`
Terminal not OK	DSR	`ESC [ 3 n`
Device status report (request status of printer)	DSR	`ESC [ ? 1 5 n`
Response:
Printer ready	DSR	`ESC [ ? 1 0 n`
Printer not ready	DSR	`ESC [ ? 1 1 n`
No printer	DSR	`ESC [ ? 1 3 n`
Device status report (report cursor position)	DSR	`ESC [ 6 n`
Cursor position report	CPR	`ESC [ Pl ; Pc R`
Device attributes (what are you)	DA	`ESC [ c`
Device attributes (what are you)	DA	`ESC [ 0 c`
Identify terminal (what are you)	DECID	`ESC Z`
NOTE: `ESC Z` is not recommended.
Device attributes response: VT102	DA	`ESC [ ? 6 c`

Reset

Name	Mnemonic	Sequence
Reset to initial state	RIS	`ESC c`

Tests and adjustments

Name	Mnemonic	Sequence
Screen alignment display (fill screen with "Es")	DECALN	`ESC # 8`
Invoke confidence test (power-up test)	DECTST	`ESC [ 2 ; 1 y`
Invoke confidence test (data loopback test; requires test connector)	DECTST	`ESC [ 2 ; 2 y`
Invoke confidence test (EIA modem control test; requires test connector)	DECTST	`ESC [ 2 ; 4 y`
Invoke confidence test (repeat power-up test continuously until failure or power-off)	DECTST	`ESC [ 2 ; 9 y`
Invoke confidence test (repeat data loopback test continuously until failure or power-off; requires test connector)	DECTST	`ESC [ 2 ; 1 0 y`
Invoke confidence test (repeat EIA test continuously until failure or power-off; requires test connector)	DECTST	`ESC [ 2 ; 1 2 y`
Invoke confidence test (printer port data loopback test; requires test connector)	DECTST	`ESC [ 2 ; 1 6 y`
Invoke confidence test (repeat printer port data loopback test continuously until failure or power-off; requires test connector)	DECTST	`ESC [ 2 ; 2 4 y`

Keyboard LEDs

Name	Mnemonic	Sequence
Load LEDs (L1 off)	DECLL	`ESC [ q`
Load LEDs (L1 off)	DECLL	`ESC [ 0 q`
Load LEDs (L1 on)	DECLL	`ESC [ 1 q`

VT52 Compatible Mode

Modes	Sequence
Enter ANSI mode	`ESC <`

Keypad Character Selection

Name	Sequence
Enter alternate keypad mode	`ESC =`
Exit alternate keypad mode (Numeric keypad mode)	`ESC >`

NOTE: VT52 alternate keypad and numeric keypad mode different than ANSI.

Character Sets

Name	Sequence
Special graphics character set	`ESC F`*
Select US/UK character set (as determined by the US/UK character SET-UP feature)	`ESC G`
* Same as special character and line drawing set in ANSI mode.

Cursor Position

Name	Sequence
Cursor up*	`ESC A`
Cursor down*	`ESC B`
Cursor right*	`ESC C`
Cursor left*	`ESC D`
Cursor to home	`ESC H`
Direct cursor address	`ESC Y Pl Pc†`
Reverse line feed	`ESC I‡`
* Same when sent from the terminal.
† Line and column numbers for direct cursor address are single character codes whose values are the desired number plus 37₈. Line and colum numbers start at one.
‡ The last character of the sequence is an uppercase i (111₈).

Erasing

Name	Sequence
Erase to end of line	`ESC K`
Erase to end of screen	`ESC J`

Print Commands

Name	Sequence
Enter auto print mode	`ESC ^`
Exit auto print mode	`ESC _`
Enter printer controller mode	`ESC W`
Exit printer controll mode	`ESC X`
Print screen	`ESC ]`
Print cursor line	`ESC V`

Reports

Name	Sequence
Identify (what are you)	`ESC Z`
Response: VT102 (same as VT52)	`ESC / Z`