DSR—User-Defined Keys (VT Level 4 Only)

The host asks if the user-defined keys (UDKs) are locked or unlocked.

Format

Exchange Sequence Meaning
Request
(Host to terminal)
CSI ? 25 n The host asks if UDKs are locked or unlocked.
Possible responses
(Terminal to host)
CSI ? 20 n UDKs are unlocked.
CSI ? 21 n UDKs are locked.