DA2

AI-Generated Content

This page was generated with the assistance of AI and may contain inaccuracies. It is intended as a placeholder for future human verification. If you spot issues ahead of its initial review, please report them on GitHub!

Standard

DA2 (Secondary Device Attributes) is a CSI sequence that queries the terminal for its type and firmware version.

Syntax

CSI > c           DA2 request (query)
CSI > Pp ; Pv ; Pc c   DA2 response

Formal syntax

(* Request *)
DA2-request  = 0x1b, "[", ">", [ "0" ], "c" ;

(* Response *)
DA2-response = 0x1b, "[", ">", Pp, ";", Pv, ";", Pc, "c" ;
Pp = digit, { digit } ;                 (* terminal type *)
Pv = digit, { digit } ;                 (* firmware version *)
Pc = digit, { digit } ;                 (* ROM cartridge / always 0 *)
digit = "0" | "1" | "2" | "3" | "4"
    | "5" | "6" | "7" | "8" | "9" ;

Description

Per the VT510 manual, the host sends CSI > c (or CSI > 0 c) to request secondary device attributes. The response contains three values:

Pp — Terminal type identifier
Pv — Firmware/software version number
Pc — ROM cartridge registration number (always 0 on modern terminals)

Common terminal type identifiers

Value	Terminal
`0`	VT100
`1`	VT220
`2`	VT240 / VT241
`41`	XTerm (commonly used)
`65`	VT510 / VT520

Modern terminal emulators report different values. For example, XTerm reports 41 for Pp and its patch level for Pv. Some terminals (e.g., iTerm2, kitty) use unique identifiers.

note

DA2 is commonly used for terminal identification in conjunction with DA1. However, relying on DA2 for feature detection is fragile since terminals may report any values they choose. The XTVERSION query or DECRQM are more reliable for specific feature detection.

Examples

printf '\e[>c'
# Typical XTerm response: ESC[>41;351;0c

Specifications

Specification	Section
VT510 Reference	—

Terminal support

Terminal	Support	Version	Notes
Terminal Emulators
Alacritty	✓	v0.6.0
Bobcat	✓	0.9.0	Supported via TerminalCtrl library
contour	✓	v0.1.0
foot	✓	Yes	Implemented at csi.c:1627-1667, reports VT220 with version number
Ghostty	✓	v1.0.0
iTerm2	✓	Yes	Secondary device attributes (DA2) fully implemented with VT100CSI_DA2 token type. Reports terminal version via reportSecondaryDeviceAttribute method.
Kitty	✓	Yes	Responds with >1;PRIMARY_VERSION;SECONDARY_VERSION c
Konsole	✓	Yes	Reports secondary attributes via CSI > 1 ; 115 ; 0 c
mintty	✓	Yes	Implemented at src/termout.c:3137-3143. Reports terminal ID 77 (mintty), decimal version, and Unicode version.
mlterm	✓	Yes	Supported since early versions, customizable via secondary_da config
PuTTY	✓	0.52	Secondary DA (CSI > c) reports xterm version 136 at terminal.c:4387-4394
Rio	✓	v0.0.3
rxvt-unicode	✓	1.2	Reports CSI > 85;95;0c where 85='U' for urxvt
st	✗	No	CSI > c not handled; only ? prefix supported in parser
terminology	✓	v0.4.0	Reports as VT510 terminal (61)
VT100	✗	No
VTE	✓	Yes	Reports as VT100-ish (level 1) or VT525 (level 5) depending on build configuration
WezTerm	✓	Yes	RequestSecondaryDeviceAttributes returns VT220 with version 277
Windows Terminal	✓	Yes	Reports VT100 terminal type (0) with version 10 (1.0)
xterm	✓	Yes	VT220+ feature, extended to VT100 in xterm
xterm.js	✓	2.3.0
Multiplexers
cy	✗	No
GNU Screen	✓	v.4.2.0	CSI > c reports terminal type 83 (ASCII 'S') at src/ansi.c:1194-1196
tmux	✓	1.3	Responds with terminal type 84 (tmux)
tuios	✓	v0.0.15	Reports VT220 version 1.0
Zellij	✓	v0.12.0	Reports secondary device attributes with version number

Syntax​

Description​

Common terminal type identifiers​

Examples​

Specifications​

Terminal support​

See also​