| SPIF(4) | Kernel Interfaces Manual | SPIF(4) | 
The device minor numbers for this driver are encoded as follows:
    +---+---+---+---+---+---+---+---+ 
    | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 
    +---+---+---+---+---+---+---+---+ 
      |   |   |   |   |   |   |   | 
      |   |   |   |   |   +---+---+---> port number 
      |   |   |   |   | 
      |   |   |   |   +---------------> unused 
      |   |   |   | 
      |   |   |   +-------------------> dial-out (on tty ports) 
      |   |   | 
      |   |   +-----------------------> unused 
      |   | 
      +---+---------------------------> card number
Up to four cards are supported in the system.
Each of the serial ports has an 8 byte FIFO for receive and transmit as well as automatic hardware (RTS/CTS) flow control.
Dial-out (cua) devices are not yet supported.
| February 4, 1999 | NetBSD 6.1 |