# Selected Area Transfer Mode (SATM)

> Whether only selected areas are transmitted.

- **Sequence:** `CSI 17 h`
- **ECMA-48:** [§7.2.14 SATM – Selected Area Transfer Mode, p. 24](https://archive.org/details/ecma-48-5th-edition-june-1991/page/n37/mode/1up)
- **DEC STD 070:** [§5.10.1.3 Modes That Cannot Be Changed, p. 5-134](https://archive.org/details/bitsavers_decstandar0VideoSystemsReferenceManualDec91_74264381/page/n388/mode/1up)

Mode 17 decides whether a transmission of the screen sends only the
selected areas, or every character position regardless of them.

| State | ECMA-48 calls it | Meaning |
| --- | --- | --- |
| Reset, `CSI 17 l` | SELECT | only the selected areas |
| Set, `CSI 17 h` | ALL | every character position |

[DEC STD 070 §5.10.1.3, p. 5-134](https://archive.org/details/bitsavers_decstandar0VideoSystemsReferenceManualDec91_74264381/page/n388/mode/1up) lists it among the X3.64 modes a DEC terminal may treat as fixed,
as not applicable. The VT510 manual's [table of modes for DECRPM](https://vt100.net/docs/vt510-rm/DECRPM.html) marks it as always reset.

xterm ignores `CSI 17 h` and `CSI 17 l` ([`ansi_modes`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/charproc.c#L7399-L7424) handles only modes 2,
4, 12 and 20), and [DECRQM](https://control-codes.page/csi/decrqm/index.html.md) reports the mode as permanently
reset, `4` ([`do_ansi_rqm`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/misc.c#L5408-L5463)). libghostty-vt ignores it too, but does not recognize the
number, so it answers DECRQM with `0`. Both DECRQM cases are known
differences.

## Validation

### SATM-1: Reported as permanently reset

*A known difference: libghostty-vt does not pass this case.*

Input, one step per line:

```text
\e[17$p
```

Expected screen:

```text
|_____|
reply \e[17;4$y
```

### SATM-2: Even after it is set

*A known difference: libghostty-vt does not pass this case.*

Input, one step per line:

```text
\e[17h
\e[17$p
```

Expected screen:

```text
|_____|
reply \e[17;4$y
```

---

This is the Markdown version of <https://control-codes.page/ansi/satm/>. On that page every validation case runs live in libghostty-vt, the terminal emulation core of Ghostty, compiled to WebAssembly.

The validation cases are written in the notation described in <https://control-codes.page/notation/index.html.md>.