Interrogation sequence

In telecommunications, an interrogation sequence is a short sequence of data sent by one system in order to trigger a known response from another. An example is in radar system's identification friend or foe (IFF) signals, which send a short sequence of radio frequency pulses that trigger a known response from the aircraft's transponder, like its current altitude. Another use is with computer terminals and file transfer protocols that send out a sequence of bytes to enquire about the user's system and adjust the data it sends in response.

References

• NATO - STANAG 4193 (Technical report). NATO.
• Ranshaw, Russ (18 November 1993). The CompuServe B Plus Protocol (Technical report). CompuServe.
• DECscope Users' Manual (PDF). DEC. 1975.