The Rest of ECMA-48

ECMA-48 defines 162 control functions. Every one that a terminal has a use for has its own page on this site. The other 80 are below, grouped by what they were for: data communications, printing and typesetting, forms, and right-to-left text, the jobs ECMA-48 was written to serve besides driving a screen. Each links to its definition in the standard.

None of them is defined by DEC STD 070 or the VT510 manual, and libghostty-vt implements none of them. It ignores them, as DEC STD 070 says a terminal should ignore any function it does not implement (§3.5.1.3, p. 3-20), and so does a default xterm, as the cases below show. Three that a default xterm does act on have pages of their own: SL and SR, which it implements, and SIMD, which it takes as Scroll Down. COVERAGE.md in the repository lists all 162 functions together.

Transmission control

These come from data communications, where a terminal and a computer exchanged blocks of text over a line and acknowledged them. They mark the start and end of headings, texts, blocks and transmissions, and carry the acknowledgements and idle fill between them. A terminal emulator’s connection to its program does its own framing, so none of them has anything to do.

§	Function	p.
8.3.1	ACK, Acknowledge	33
8.3.33	DLE, Data Link Escape	39
8.3.42	EM, End Of Medium	42
8.3.45	EOT, End Of Transmission	43
8.3.49	ETB, End Of Transmission Block	43
8.3.50	ETX, End Of Text	43
8.3.84	NAK, Negative Acknowledge	50
8.3.127	SOH, Start Of Heading	65
8.3.146	STX, Start Of Text	71
8.3.150	SYN, Synchronous Idle	72

Device control and separators

DC2 and DC4 were for switching on and off an auxiliary device on the line; DC1 and DC3, their siblings, became XON and XOFF. The four information separators divide data into files, groups, records and units, for data that is not text to be shown.

§	Function	p.
8.3.29	DC2, Device Control Two	38
8.3.31	DC4, Device Control Four	39
8.3.69	IS1, Information Separator One (US, Unit Separator)	48
8.3.70	IS2, Information Separator Two (RS, Record Separator)	48
8.3.71	IS3, Information Separator Three (GS, Group Separator)	48
8.3.72	IS4, Information Separator Four (FS, File Separator)	48

Code extension and private use

Ways of escaping into another coding system, or of introducing one character with a private meaning, and two controls reserved for private use. SCI’s 7-bit form, ESC Z, is the same as DEC’s DECID, which libghostty-vt answers as a Device Attributes request.

§	Function	p.
8.3.11	CMD, Coding Method Delimiter	34
8.3.100	PU1, Private Use One	54
8.3.101	PU2, Private Use Two	54
8.3.109	SCI, Single Character Introducer	58

Input and messages

Controls for a device’s manual input, interrupting the other end, signalling a waiting message or a function key, and cancelling the character before.

§	Function	p.
8.3.8	CCH, Cancel Character	34
8.3.34	DMI, Disable Manual Input	39
8.3.43	EMI, Enable Manual Input	42
8.3.52	FNK, Function Key	44
8.3.68	INT, Interrupt	48
8.3.83	MW, Message Waiting	50
8.3.145	STS, Set Transmit State	71

Areas and fields

For forms: dividing the screen into qualified areas and selected areas with their own rules, and erasing or editing within them. Guarded areas, the one part of this that terminals took up, have their own page under SPA.

§	Function	p.
8.3.25	DAQ, Define Area Qualification	37
8.3.37	EA, Erase In Area	40
8.3.40	EF, Erase In Field	41
8.3.47	ESA, End Of Selected Area	43
8.3.115	SEE, Select Editing Extent	60
8.3.138	SSA, Start Of Selected Area	69

Page and line layout

For printers and typesetting: the size of the page and its text area, the home and limit positions of lines and pages, line spacing and partial line feeds, where lines may break, and how lines are justified and aligned.

§	Function	p.
8.3.4	BPH, Break Permitted Here	33
8.3.36	DTA, Dimension Text Area	40
8.3.73	JFY, Justify	48
8.3.85	NBH, No Break Here	50
8.3.91	PFS, Page Format Selection	52
8.3.92	PLD, Partial Line Forward	52
8.3.93	PLU, Partial Line Backward	53
8.3.102	QUAD, Quad	55
8.3.116	SEF, Sheet Eject And Feed	60
8.3.122	SLH, Set Line Home	64
8.3.123	SLL, Set Line Limit	64
8.3.124	SLS, Set Line Spacing	64
8.3.131	SPH, Set Page Home	67
8.3.132	SPI, Spacing Increment	67
8.3.133	SPL, Set Page Limit	68
8.3.134	SPQR, Select Print Quality And Rapidity	68
8.3.139	SSU, Select Size Unit	69
8.3.149	SVS, Select Line Spacing	71

Character presentation

The size, spacing, font and orientation of characters, combining two characters into one, and alternative presentations of the same character. A character-cell terminal has one fixed cell size and one font, so there is nothing for these to change.

§	Function	p.
8.3.53	FNT, Font Selection	44
8.3.54	GCC, Graphic Character Combination	44
8.3.55	GSM, Graphic Size Modification	45
8.3.56	GSS, Graphic Size Selection	45
8.3.65	IDCS, Identify Device Control String	47
8.3.66	IGS, Identify Graphic Subrepertoire	47
8.3.90	PEC, Presentation Expand Or Contract	51
8.3.107	SACS, Set Additional Character Separation	56
8.3.108	SAPV, Select Alternative Presentation Variants	57
8.3.110	SCO, Select Character Orientation	58
8.3.112	SCS, Set Character Spacing	59
8.3.118	SHS, Select Character Spacing	63
8.3.136	SRCS, Set Reduced Character Separation	68
8.3.140	SSW, Set Space Width	70
8.3.157	TSS, Thin Space Specification	73

Tabulation for typesetting

Line tabulation stops, and tab stops that align text on its leading edge, its trailing edge, its centre or a chosen character. Terminals keep only the plain character tab stops that HT, CHT, HTS, TBC and CTC use.

§	Function	p.
8.3.23	CVT, Cursor Line Tabulation	37
8.3.61	HTJ, Character Tabulation With Justification	46
8.3.144	STAB, Selective Tabulation	71
8.3.151	TAC, Tabulation Aligned Centred	72
8.3.152	TALE, Tabulation Aligned Leading Edge	72
8.3.153	TATE, Tabulation Aligned Trailing Edge	72
8.3.155	TCC, Tabulation Centred On Character	73
8.3.156	TSR, Tabulation Stop Remove	73
8.3.162	VTS, Line Tabulation Set	74

Bidirectional and directed text

Text that runs right to left, or vertically, and strings whose direction is reversed or directed. SIMD, the last of this group, has its own page.

§	Function	p.
8.3.99	PTX, Parallel Texts	53
8.3.111	SCP, Select Character Path	58
8.3.114	SDS, Start Directed String	59
8.3.130	SPD, Select Presentation Directions	66
8.3.137	SRS, Start Reversed String	69

Validation

CAT-1: Transmission controls are ignored

A
\x01\x02\x03\x04 # SOH STX ETX EOT
\x06\x10\x15\x16 # ACK DLE NAK SYN
\x17\x19          # ETB EM
\x12\x14\x1c\x1f # DC2 DC4 IS4 IS1
B

|AB______|
cursor 1,3

CAT-2: So are the independent functions

A
\e`\ea\eb\ed      # DMI INT EMI CMD
B

|AB______|

CAT-3: And the unused C1 controls

A
\eB\eC\eF\eG\eI   # BPH NBH SSA ESA HTJ
\eJ\eK\eL\eQ\eR   # VTS PLD PLU PU1 PU2
\eS\eT\eU\e[0[   # STS CCH MW SRS
B

|AB______|

CAT-4: The control sequences without an intermediate

A
\e[Y\e[O\e[N\e[o   # CVT EA EF DAQ
\e[Q\e[0[\e[\\\e[0]  # SEE SRS PTX SDS
B

|AB______|
cursor 1,3

CAT-5: And those with a space

A
\e[\sB\e[\sC\e[\sD\e[\sE\e[\sF\e[\sG\e[\sH  # GSM GSS FNT TSS JFY SPI QUAD
\e[\sI\e[\sJ\e[\sK\e[\sL\e[\sM\e[\sO      # SSU PFS SHS SVS IGS IDCS
\e[\sS\e[\sT\e[\sU\e[\sV\e[\sW\e[\sX\e[\sY  # SPD DTA SLH SLL FNK SPQR SEF
\e[\sZ\e[\s[\e[\s\\\e[\s]\e[\s^\e[\s_    # PEC SSW SACS SAPV STAB GCC
\e[\s`\e[\sa\e[\sb\e[\sc\e[\sd          # TATE TALE TAC TCC TSR
\e[\se\e[\sf\e[\sg\e[\sh\e[\si\e[\sj\e[\sk  # SCO SRCS SCS SLS SPH SPL SCP
B

|AB______|
cursor 1,3

A default xterm drops every one of these: its parse tables send them to the ground state without acting on them (csi_table, csi_sp_table), and so does libghostty-vt. The one escape sequence above that xterm can act on is ESC F, which moves the cursor to the lower left corner only when the hpLowerleftBugCompat resource is set for old HP-UX programs, and it is off by default (CASE_HP_BUGGY_LL).