Fax with isdn4linux
  ===================
  
  When enabled during kernel configuration, the tty emulator
  of the ISDN subsystem is capable of the Fax Class 2 commands.
  
  This only makes sense under the following conditions :
  
  - You need the commands as dummy, because you are using
    hylafax (with patch) for AVM capi.
  - You want to use the fax capabilities of your isdn-card.
    (supported cards are listed below)
  
  
  NOTE: This implementation does *not* support fax with passive
        ISDN-cards (known as softfax). The low-level driver of
        the ISDN-card and/or the card itself must support this.
  
  
  Supported ISDN-Cards
  --------------------
  
  Eicon DIVA Server BRI/PCI
  	- full support with both B-channels.
  
  Eicon DIVA Server 4BRI/PCI
  	- full support with all B-channels.
  
  Eicon DIVA Server PRI/PCI
  	- full support on amount of B-channels
  		depending on DSPs on board.
  
  
  
  The command set is known as Class 2 (not Class 2.0) and
  can be activated by AT+FCLASS=2
  
  
  The interface between the link-level-module and the hardware-level driver
  is described in the files INTERFACE.fax and INTERFACE.
  
  Armin
  mac@melware.de