[from the ASCII mnemonic ENQuire for 0000101] An on-line convention for querying someone's availability. After opening a talk mode connection to someone apparently in heavy hack mode, one might type SYN SYN ENQ? (the SYNs representing notional synchronization bytes), and expect a return of ACK or NAK depending on whether or not the person felt interruptible. Compare ping, finger, and the usage of FOO? listed under talk mode.