Friday, June 28, 2013

Getting the TP-Link TL-WN772N(C) USB WLAN stick to work

After installing Debian wheezy on the N54L microserver I wanted to setup a stable WLAN connection. The stick should have out-of-the-box kernel support. First I bought a cheap ISY IWL 2000 N150 WLAN USB micro adapter (probably a branded Belkin F7D1102). I contains a Realtek chipset and although it did seem to work on my laptop with Sid running, I did not get it to work on the server. I refused to download and compile third-party software.

So I searched this site. I got the impression, that the "only" recent chipsets with reasonable support in the Linux kernel are Atheros chipsets(?). Checking the local suppliers I decided to buy a TP-Link TL-WN722NC USB stick. I've downloaded the firmware-atheros package and loaded the ath9k_htc module and voilà, the stick is running:

ath9k_htc              48534  0 
ath9k_common           12728  1 ath9k_htc
ath9k_hw              322112  2 ath9k_common,ath9k_htc
ath                    21370  3 ath9k_hw,ath9k_common,ath9k_htc
mac80211              192806  1 ath9k_htc
cfg80211              137243  3 ath,mac80211,ath9k_htc
usbcore               128741  5 ehci_hcd,ohci_hcd,usbhid,ath9k_htc
Bus 001 Device 003: ID 0cf3:9271 Atheros Communications, Inc. AR9271 802.11n
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          255 Vendor Specific Class
  bDeviceSubClass       255 Vendor Specific Subclass
  bDeviceProtocol       255 Vendor Specific Protocol
  bMaxPacketSize0        64
  idVendor           0x0cf3 Atheros Communications, Inc.
  idProduct          0x9271 AR9271 802.11n
  bcdDevice            1.08
  iManufacturer          16 ATHEROS
  iProduct               32 USB2.0 WLAN
  iSerial                48 12345
  bNumConfigurations      1

To setup the connection I decided to install the network-manager package and write the configuration file myself:





wlan1     IEEE 802.11bgn  ESSID:"<ESSID>"
          Mode:Managed  Frequency:2.467 GHz  Access Point: <MACADDR>
          Bit Rate=54 Mb/s   Tx-Power=20 dBm
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=49/70  Signal level=-61 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:61   Missed beacon:0

The connection comes up and it seems pretty stable. After two weeks of operation there were still no connection losses or time outs. After lease time has been reached, the IP address gets renewed. And that's it! The stick runs perfectly fine for me and I'm happy with it.

1 comment:

  1. I've measured the power consumption of this little server and it turns out, that this USB card uses 10W. This is almost 1/4 of the power consumption of the whole system.