ENQ Enquiry

On receiving ENQ, the terminal sends its answerback message to the host. ECMA-48 says only that ENQ is “a request for a response from a receiver”, and leaves its use to ISO 1745. DEC terminals answer with a message the user stores in the terminal’s setup, so that a host on the far end of a modem line could ask who had called. DEC STD 070 has ENQ only in an appendix of exceptions to the standard, and says the message “is empty by factory default”. An empty message means nothing is sent at all.

Nothing on the screen changes, and the cursor does not move.

libghostty-vt asks its host for the message. Ghostty’s enquiry-response setting, empty by default, is that message. The cases here run with Ghostty’s default, so ENQ gets no answer, as it does on a DEC terminal fresh from the factory.

Validation

ENQ-1: No answerback message

AB
\x05
C

|ABC__|
cursor 1,4
reply none