What model 2wire? The model number is on the serial number tag on the bottom of the case.
You should not be using the USB connection for connectivity. You should be using the ethernet connection. The USB port is useful for configuration and it's possible to use it to surf the web, but it's not a great idea.
Could you describe how you have everything wired and cabled?
The way you should be using this is to have the Home Portal login to your SBC PPPoE account. The two computers then plug into the ethernet ports on the Home Portal. The USB port is not used. You should NOT be using Enternet 300 for logging into the SBC DSL network.
Once this is working (and only after it's working), dive into the XP Control Panel and remove all the useless SBC/Yahoo crap that SBC supplied as it's totally un-necessary and I suspect causes problems. See:administration (via ethernet), try: http://172.16.1.1 or http://172.16.0.1
It's not the adapter. It's probably the power save or power management "feature" on either the USB port driver or the computer that's causing problems.
The Home Portal *IS* a router. You should be using it as a router, not as a single machine modem via USB as apparently you have it configured.
Frankly, methinks you have a mess that is going to require some substantial tinkering with the setup to get it setup correctly. I suggest you find a local expert with SBC DSL experience and have them clean up your system.
By the way, if you've read any of my junk in this newsgroup, you'll find that I detest generalities and lack of numeric information. Pretend you went to an automobile machanic for help with your vehicle using your same general format. "I have a car with a red paint job". Not very useful. Kindly supply the make and model of your PC, with which mutation of XP you're using, and what hardware are you using.
You'll get better answers if you supply:
- What problem are you trying to solve?
- What do you have to work with? (hardware and software list)
- What have you done so far and what happened?