GTK ACX Tool supports following command line arguments:

gacxtool <interface>
Interface name.
Default value is 'acx0'.

gacxtool -i <interface>
Interface name.
Default value is 'acx0'.

gacxtool -b <bandwidth>
This value is used for to set traffic history graph size.
Default value is 256.

gacxtool -d <delay>
Number of timeouts before updating signal and traffic data.
Default value is 1.

gacxtool -h
Shows short help information.

gacxtool -r
Switches off absolute values display in 'Signal' and 'Traffic' tabs.
Default value is 'on'.

gacxtool -v
Switches on console output.
Default value is 'off'.

gacxtool -t <timeout>
Driver poll timeout in milliseconds.
Default value is 100.

These arguments could be used in any combination.
If your interface is acx0 than you can use gacxtool without any arguments.

Latest version

This version could be used just with FreeBSD ACX100 driver.

Current version
FreeBSD port