After struggling for days... it's now working under my asterisk.
Next step: Using the land line to call asterisk and I key in a 11 digit phone number then route thru GV.
Currently I used a softphone to make a GV call under asterisk without any problem. But how to setup by using land line? Any reference for that? Thanks.
If you have an inbound PSTN trunk in your Asterisk box which can detect your calling ID to direct your call to an IVR. The IVR can let you make other outbound calls using other trunks such as GV.