CONFIG_ISDN_DRV_ICN
  This enables support for two kinds of ISDN-cards made by a German
  company called ICN.  2B is the standard version for a single ISDN
  line with two B-channels, 4B supports two ISDN lines.  For running
  this card, additional firmware is necessary, which has to be
  downloaded into the card using a utility which is distributed
  separately.  See <file:Documentation/isdn/README> and
  <file:Documentation/isdn/README.icn> for more
  information.

