Use a USB phone without Softphone

I must make a low cost VoIP platform on a embedded card. I wish install Asterisk on. The users connect USB phone to my card, and I want to know, if is it possible to use the stream of the USB phone directly in asterisk, without a softphone as X-Lite.

So can I redirect the in/output of the USB phone in the in/output of asterisk as a stream? And asterisk make the compress of the voice.

Is it possible? If yes can you tell me the way to make that.
If not, can you tell me a another solution, i can’t use a softphone application because i’m scare that the embedded card was not powerful for that.

Thanks by advance.
Sorry for my bad english