DA1—Primary Device Attributes

In this DA exchange, the host asks for the terminal's architectural class and basic attributes.

Host Request

The host uses the following sequence to send this request:

CSI
9/11
c
6/3
or CSI
9/11
0
3/0
c
6/3

Terminal Response

The terminal responds by sending its architectural class and basic attributes to the host. This response depends on the terminal's current operating VT level.

Response from North American Terminal
CSI
9/11
?
3/15
6
3/6
4
3/4
;
3/11
Ps1
3/n
;
3/11
...
...
Psn
3/n
c
6/3
Response from International Terminal
CSI
9/11
?
3/15
6
3/6
4
3/4
;
3/11
Ps1
3/n
;
3/11
...
...
Psn
3/n
c
6/3

Parameters

Ps1 ; . . . Psn
reports different device attributes between the North American terminal and the international terminal.

The value of the first parameter is encoded so a simple range check can be performed to determine the basic service class and level of the device. The VT510 is a level 4 terminal so its service class code is 64. The following extensions to level 4 are provided:

Ps Meaning
1 132 columns
2 Printer port
4 Sixel
6 Selective erase
7 Soft character set (DRCS)
8 User-defined keys (UDKs)
9 National replacement character sets (NRCS)
(International terminal only)
12 Yugoslavian (SCS)
15 Technical character set
18 Windowing capability
21 Horizontal scrolling
23 Greek
24 Turkish
42 ISO Latin-2 character set
44 PCTerm
45 Soft key map
46 ASCII emulation

Primary DA Example

Here is a typical primary DA exchange.

Exchange Sequence Meaning
Request
(Host to VT510)
CSI c or CSI 0 c The host asks for the terminal's architectural class code and supported extensions.
Response—N.A. (VT510 to host) CSI ? 64; 1; 2; 7; 8; 9; 15; 18; 21; 44; 45; 46 c The terminal is a class 4 device (64) and supports the Ps parameters listed above.
Response— International (VT510 to host) CSI ? 64; 1; 2; 7; 8; 9; 12; 15; 18; 21; 23; 24; 42; 44; 45; 46 c The terminal is a class 4 device (64) and supports the Ps parameters listed above.