usb.host.hid_count

usb.host.hid_count

This command displays the number of USB Human Interface Devices (HIDs) connected to the printer.
Refer to http://www.usb.org for further details on USB device types.

Getvar

To retrieve the number of USB HIDs connected to the printer:
! U1 getvar "usb.host.hid_count"
Result
When no devices are attached:
! U1 getvar "usb.host.hid_count" "0"