In computer communications, enquiry is a transmission-control character that requests a response from the receiving station with which a connection has been set up. It represents a signal intended to trigger a response at the receiving end, to see if it is still present. The response, and answer-back code to the terminal that transmitted the WRU signal, may include station identification, the type of equipment in service, and the status of the remote station.

Some teleprinters had a "programmable" drum, which could encode 20 or 22 characters, programmable by breaking tabs off a drum. This sequence could be transmitted upon receipt of an enquiry signal, if enabled, or by pressing the "Here is" key on the keyboard.

The 5-bit ITA2 already has an enquiry character, as do the later ASCII

ASCII

The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

 and EBCDIC

EBCDIC

Extended Binary Coded Decimal Interchange Code is an 8-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems....

.

DEC

Digital Equipment Corporation

Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 terminals respond to enquiry with the answerback message.

In some computer terminals and EMACS

Emacs

Emacs is a class of text editors, usually characterized by their extensibility. GNU Emacs has over 1,000 commands. It also allows the user to combine these commands into macros to automate work.Development began in the mid-1970s and continues actively...

, it moves the cursor to the end of current line.

External links

• Browser Test Page for Unicode Character 'ENQUIRY' (U+0005)
• Enquiry Character from ComputerHope.com
• Enquiry character from SmartComputing.com