2. Sometimes used to describe what communications people call "shift characters", such as the ESC that leads control sequences for many terminals, or the level shift indicators in the old 5-bit Baudot codes.
3. In personal communication, using methods other than electronic mail, such as telephone or snail-mail.
This use confuses "out-of-band" with "out-of-range". It is actually a clear example of in-band signalling since it uses the same "channel" for control and data.
Compare hidden flag, green bytes, fence.