* The ISDN adapters supported by this release of the driver
          package can send and receive analog calls and also 64Kbs restricted
          digital ISDN calls.  In the case of ISDN calls, the firmware
          assumes the caller begins data transfer in sync PPP mode, and 
          received sync PPP packets are translated into async PPP
          packets and passed up through the standard asynchronous devices.
          Transmitted async PPP packets are likewise translated into
          sync PPP packets before being transmitted over the ISDN link.
          The driver package DOES NOT support the isdn4linux interface.