This package provides source code for the rt2570 driver for linux. this driver supports usb wireless network cards with the ralink rt2500usb chipset. an alternate driver, rt2500usb, is available in the rt2x00-source package and in the linux kernel from version 2.6.24.

in order to compile the driver you need the kernel sources (or the linux-headers for the linux-image packages from debian). for compile instructions look into /usr/share/doc/rt2570-source/readme.debian or simply use the module-assistant utility.