FETM Format Effector Transfer Mode
Whether formatting functions may be added to what is transmitted.
CSI 14 h/l
- ECMA-48
- §7.2.6 FETM – Format Effector Transfer Mode, p. 22
- DEC STD 070
- §5.10.1.3 Modes That Cannot Be Changed, p. 5-134
Mode 14 decides whether the terminal may add formatting functions of its own to what it transmits, or only passes on the ones it stored under FEAM.
| State | ECMA-48 calls it | Meaning |
|---|---|---|
Reset, CSI 14 l | INSERT | formatting functions may be inserted |
Set, CSI 14 h | EXCLUDE | only those stored under FEAM are sent |
DEC STD 070 §5.10.1.3, p. 5-134 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 marks it as always reset.
xterm ignores CSI 14 h and CSI 14 l (ansi_modes handles only modes 2, 4, 12 and 20), and DECRQM reports the mode as permanently reset, 4 (do_ansi_rqm). libghostty-vt ignores it too, but does not recognize the number, so it answers DECRQM with 0. Both DECRQM cases are known differences.
Support
| Terminal | Version | Support | Notes |
|---|---|---|---|
| VT220 | manual, 2nd ed., 1984 | No | not in the manual, whose table of ANSI modes has only KAM, IRM, SRM and LNM |
| VT510 | manual, 1st ed., 1993 | No | listed as permanently reset |
| xterm | patch 412, xterm-411a | No | ignored; DECRQM reports it permanently reset, 4 |
| libghostty-vt | 0f171f6 | No | ignored; DECRQM answers 0 (FETM-1, FETM-2) |
| ConEmu | build 230724, its documentation | No | not in its ANSI escape codes |
Validation
FETM-1: Reported as permanently reset
\e[14$p
|_____|
reply \e[14;4$y
FETM-2: Even after it is set
\e[14h
\e[14$p
|_____|
reply \e[14;4$y