When connecting my HT-286 directly to the "LINE" jack on my fax machine (Sharp UX355LR), the dial tone seems to come and go. I press the "Speaker" button for on-hook dial, and the HT-286 light turns green (and stays green as long as the machine is off hook). Dial tone is heard, but then briefly goes away, and then briefly comes back, etc, even before dialing...

Clearly it's a problem with the device, and not VOIPo -- It works 100% correctly when connected to a regular phone.

Any ideas?