The SPA3000 Auto PSTN Fallback works when it is set to yes. You should be able to dial local numbers when you have the device powered off (power failure or physically off) without dialing a prefix number 9 as shown on the dial plan.
Step 1: Access the SPA3000's web-based setup page. For instructions, click here.
Step 2: Click Admin Login then advanced.
Step 3: Click Line 1 and look for VoIP FallbackTo PSTN and set Auto PSTN Fallback to yes.