out-of-band

2 definitions found

out-of-band - Free On-line Dictionary of Computing (26 May 2007) :

  out-of-band
  
     1. <communications> 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. <software> 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)
  

out-of-band - Jargon File (4.4.4, 14 Aug 2003) :

  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.