Use a D-Link DWL-G122 USB WiFi Dongle - revisited

Feb 14, '06 06:26:00AM

Contributed by: simonvx

Let's say you have an "old" Mac you want to wirelessly connect to your AirPort network. In my case, it's an eMac. Like me, you probably don't want to buy an expensive AirPort Extreme card. It's worse if you have an old G3 CRT iMac: the already-expensive card needs an exepensive adapter! So you look on the internet for a cheap USB WiFi dongle solution, like many of your PC friends own. What? They don't make any of these for Macs? D-Link made one two years ago, but its new version (the DWL-G122) doesn't support OS X any more. So I came across a one-year-old hint here, which made me purchase it, because the hint (and replies) stated that "rev B1" of this dongle used a chipset that was Mac-compatible ... and that the maker (Ralink) had an OS X driver available on their site.

But I quickly was disappointed: I could only use it when I had no password assigned to my wireless network! It just wouldn't work when my WEP encryption was enabled. After much research, and the help of others in the Ralink forums, I found a solution. Put simply (for you quick-minded network genies), you need to enable WPA Personal encyption (instead of WEP, which seems to be totally broken with this version of the driver) and use a 13-character password.

For other, less-exeperienced users, I have written a very detailed walkthrough, which is a combination of the old hint, personal experience, info found on Apple's help pages, and elsewhere on the internet.

First, I assume you are on a Mac running OS X 10.4 (it may also work under 10.3, because Ralink provides drivers for Panther, too), and that you are within range of a wireless network (in my case, an AirPort Extreme Base Station) and not connected via Ethernet. You also must not have an AirPort card in this Mac, as having two WiFi devices that near may damage one or both. I know, why would you want to connect a USB WiFi dongle when you have AirPort hardware? It doesn't make sense, but some folks like to try stuff just for fun!

Second, and this is the "tricky" thing (well, for me it was anyway), you must set your AirPort Extreme Base Station to use WPA Personal encyption. Why? Because WEP encryption seems to be simply non-working with this version of the Ralink driver. So unless you want to use an unprotected wireless network (which is totally unsafe), you must use WPA. Note: I did not find any successful reports of WEP working with my kind of config, hence my self-made conclusion and recommendation to switch to WPA (thanks to "Ryhs" in the Ralink forums).

Luckily, changing your encryption to WPA is easy. Just go in your AirPort Admin Utility (with a Mac that can connect to the Base station, of course), and under the AirPort tab, click on Change Wireless Security..., then choose WPA2 Personal. Enter a password that is preferably 13 characters long. Why 13 characters? In Apple's AirPort help, they say this length enhances compatibility with non-Apple computers, and I suspect that, when you use a WiFi dongle, the AirPort Base Station has problems recognizing that a true Mac is trying to connect to it!. For the Encryption Type, I chose WPA and WPA2. Click OK.

Of course, if you are using a closed network, you must enter your dongle's MAC address (see label on the dongle, look for "MAC ID") under the Access Control tab, like you would do for any computer you want to give permission to access your wireless network.

Click Update and let your Base Station reboot. The Mac you just used to update these settings won't be able to reconnect -- unless you already had a 13-letter password! You will need to go in your AirPort menulet (in your menu bar, where the clock, etc. is) and connect to it, entering your newly-created password. If this works (check if Internet is live), you did everything right so far.

Now you're ready to go back to your unwired computer that wants to connect wirelessly. Reminder: do not connect the dongle yet. Other reminder: you absolutely must have the D-Link DWL-G122 USB WiFi Dongle rev. B1. This "rev B1" thing is crucial, as it is this version of the dongle that uses the Ralink 2500 chipset, which Ralink has drivers for, but not D-Link (if D-Link did, this hint wouldn't exist). Here we go:

  1. Download the Ralink driver from their drivers page. Choose one that matches your OS X version. I picked the latest one, for OS X 10.4.X, dated 2005/11/29 and numbered "Drv1.2.0.0" (it's at the bottom of the page, under "Macintosh / 11g-RT2500").

  2. Install the driver, and restart the computer when prompted. Do not connect the dongle yet!

  3. When fully rebooted, connect the dongle. WirelessUtilityUSB app should come up (it has a generic icon). Don't touch it yet.

  4. Go into System Preferences > Network. You should get a notice telling you that a new network interface was found. Click Apply Now to acknowledge it, and something like "Ethernet Adpater (en1)" should appear where you probably have "Internal Modem" and "Built-in Ethernet" already listed.

  5. Click this new interface and configure it to connect to your wireless network. For example, for my setup, it is easy: under the TCP/IP tab, I choose Configure IPv4 Manually, then I enter the IP address I had when I was Ethernet-wired, fill in the Subnet Mask with the usual 255.255.255.0, type in my AirPort Base Station's IP address in the Router field, and my ISP's DNS Servers' addresses, as usual, then click Apply Now.

  6. Switch back (via the Show menu) to Network Status. You should see a green light next to "Ethernet Adpater (en1)," meaning the device is active ... and meaning you did great so far!

  7. Go back to the WirelessUtilityUSB app. Note: Your dongle lights must be flashing by now.

  8. It may take a few seconds, but your wireless network (and all others within range) should appear under the Site Survey tab. In the SSID column, you should see its name, or if you have a "closed network" (a.k.a. "Hidden SSID" or, in other words, if the wireless network you want to connect to does not broadcast its name), you will only see its MAC address in the BSSID column.

  9. Click Connect at the bottom of the window. If you have a closed network, you will be prompted to enter the exact network name. If not, you will be immediately brought to the Authentication window.

  10. Authentication window: For Authentication Type, choose WPA-PSK. For Encryption Type, choose TKIP. In the WPA Pre-Shared Key field, enter your 13-character password. Click OK.

  11. After a short moment (for me, it takes about 15-20 seconds), a weird green icon should appear in the unnamed column next to the SSID column, meaning you're connected to the Base Station! A "Connected" status message should also appear at the bottom.

You're done! WirelessUtilityUSB must remain open all the time, and, assuming all your Network settings in System Preferences are correct, you should be able to surf the internet wirelessly. Don't be surprised: this thing is slower that an AirPort card, and I find it slower to show a page for the first time in the session everytime I open Safari. Maybe it's just me.

Another thing: every time you put the computer to sleep or reboot, you'll probably have to unplug-deplug the dongle to "wake it up" (driver problem again). Then you must repeat steps seven to eleven to reconnect. I know, WirelessUtilityUSB app provides the Profiles feature (which, I guess, lets you save settings for each network you want to connect to, and for simple, quick reconnection), but I couldn't get it to work. Feels like a flakey driver, but it does the job for me.

Thomas Walter came up with a solution for the reboot problem, which I have yet to test. You can download his kernel extension (a dummy driver which simulates pulling and replacing the dongle). If you find it useful, please donate ;-)

I hope this long hint helped you! Please comment or email me (via the author link at the top of the hint) if you have questions.

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Mac OS X Hints
http://hints.macworld.com/article.php?story=200602140626039