On Thursday 05 July 2007 22:22, you wrote:

Just call up your asterisk box while at home, using the wifi so the call is free.

Sure, and waste 3x the bandwidth at a major drop in quality (digital to analog to digital, even before final termination!)

Have the asterisk give you a dialtone to dial out with, and just never hang up.

Asterisk doesn't give dialtones on its own except on actual analog lines.