This file briefly explains how the device files are used.

When the driver module is loaded, each ASI transmit interface
is assigned a number between 0 and 127. Similarly, each ASI receive interface
is assigned a number. The first interface detected in each case
is called interface 0, the second is called interface 1, and so on.

Each interface is represented by a device file.
Device files have characteristic major and minor numbers.
The major number determines which driver responds to activity directed
at that file. DVB ASI drivers respond to activity directed at
files with major number 61 by default. The minor number may be used
by the driver for any purpose. The DVB ASI API uses it to
identify the interface associated with that file.
The 7 least significant bits of the minor number hold the interface number,
while bit 8 is zero for transmitters and one for receivers.
Thus, transmitters use minor numbers 0 to 127, and receivers use
minor numbers 128 to 255. The mkdev.asi script creates device files
called /dev/asitx* and /dev/asirx* which use these numbers.

