Outofband

2 definitions found

From Jargon File (4.3.1, 29 Jun 2001) [jargon]:

  out-of-band adj. [from telecommunications and network theory] 1. In
     software, describes values of a function which are not in its `natural'
     range of return values, but are rather signals that some kind of
     exception has occurred. Many C functions, for example, return a
     nonnegative integral value, but indicate failure with an out-of-band
     return value of -1. Compare {hidden flag}, {green bytes}, {fence}. 2.


     Also 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 email, such as
     telephones or {snail-mail}.
  
  

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  out-of-band
       
          1.  The exchange of {call control} information
          on a dedicated channel, separate from that used by the
          telephone call or data transmission.
       
          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}.
       
          4.  Values returned by a {function} that are not in
          its "natural" {range} of return values, but rather signal some
          kind of {exception}.  Many {C} functions that normally return
          a non-negative integer return -1 to indicate failure.
       
          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}.
       
          [{Jargon File}]
       
          (2001-04-08)