Sunday, 16 September 2012

Wifi fettling - rt2870sta / rt5370sta confusion

I'm redecorating my dining room - which is also where my computer lives. Part of this involved re-siting my computer. Rather than run a cable across the room for my internet connection I thought I'd use wireless. I had an old 3com card in my parts drawer - but it appears my kids / the dog had been playing with it. I've always been very happy with 3com kit, but since money is rather tight I decided to go with a basic USB adapter. A quick Google and I found a few people saying that this one worked with Linux.

It's tiny!

It comes with a mini cd which includes source code for Linux drivers! Yeah! Reading the docs, it described how to build and install the RT2870STA kernel module. But my PCLinuxOS 2012 installation  comes with the driver and firmware. So I spent an hour or so trying to get it to work to no avail.

Ho hum, let's try the supplied driver. No configure - just make and make install. But it didn't generate a rt28750sta.ko, instead I got a rt5370sta.ko - it seems that the documentation bundled with the code is out of date. Really I should have gotten the hint when I checked the device with lsusb:

Bus 001 Device 005: ID 148f:5370 Ralink Technology, Corp.

After doing a modprobe I was up and running.

I've disabled the ONBOOT setting for my wired ethernet and enabled it for the new device via drakconf and it all works perfectly (even little green bars in the system tray).

10 feet from the router I get a good signal. I don't know how well it would work at a greater distance with such a small antenna (but our phones get a signal from quite a distance away). It's not really a problem for this machine since it's never going to be very far from the access point.

Link Quality=100/100  Signal level:-52 dBm  Noise level:-83 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

(note to self must remember to add mac address to admin ACL and change the forwarding on access point).

I also got a new desk on Amazon. It's compact and (importantly) feels very solid. The only downsides were that it was a bit tricky to assemble and with my PC on the bottom shelf, the fan is rather noisy (shelf resonates a bit).

1 comment:

  1. While the 5370 device works as a NIC, I get a lot of noise in my logs from the fact it doesn't properly implement several ioctls - as a result a lot of tools (including iptraf and ethtool) can't even see the device. So until such time as I see a better driver, I wouldn't recommend this for anyone wanting to pro-actively manage their network / use it as a network investigation tool.