[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

satisfied customer

  W. Curtiss Priest wrote in a message to Mike Bilow:
   WCP> The POTS local loop connects to some 'device' at the CO that
   WCP> converts analog to digital.  An ISDN line connects to a
   WCP> different 'device'. converting a different  analog signal to
   WCP> digital.
  ISDN is not analog; it is digital.  Because of this, the "device" to which you
  refer has sufficient knowledge about the internal structure of the information
  to extract only the real information, eliminating analog noise that may have
  crept into the analog representation of the digital information as it travels
  on its copper wire pair.
  With POTS, the "device" in question knows nothing about whether the circuit it
  is maintaining is a V.34 modem connection, two humans talking, or dead air.  It
  cannot tell what information is real data and what is noise that has been
  introduced along the way, so it must simply attempt to relay the whole
  conglomeration as faithfully as possible.
   WCP> My question is:  for the purposes of digital communications
   WCP> (i.e. digitized data emminating from a PC, etc.) is the
   WCP> first device more or less expensive than the second device?
  The ISDN tap may be functionally simpler, even if more expensive.  The real
  costs here are determined by many complicated factors.
  -- Mike