printers

udev/eudev uses the lp group for some printing devices but mdev not.

KERNEL=="parport[0-9]*", GROUP="lp"
SUBSYSTEM=="printer", KERNEL=="lp*", GROUP="lp"
SUBSYSTEM=="ppdev", GROUP="lp"
KERNEL=="lp[0-9]*", GROUP="lp"
KERNEL=="irlpt[0-9]*", GROUP="lp"
SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0701??:*", GROUP="lp"

This is what I came up with but I am not sure about the last line:

parport[0-9]*		root:lp 0660
SUBSYSTEM=printer;lp*	root:lp 0660
SUBSYSTEM=ppdev;.*	root:lp 0660
lp[0-9]*		root:lp 0660
irlpt[0-9]*		root:lp 0660
SUBSYSTEM=usb;DEVTYPE=usb_device;ID_USB_INTERFACES=*:0701..:*;.*	root:lp 0660 */lib/mdev/usbdev

These instructions here uses SUBSYSTEM=usb;PRODUCT=4b8/7/100;.* root:lp 660 */lib/mdev/usbdev. Don't know which is better.