Assuming you have an OBi110 and your PrimaryLine is SP1 (Google Voice) ...
Physical Interfaces -> PHONE Port -> OutboundCallRoute:
{([1-9]x?*(Mpli)):pp},{(<#:>):li},{(<911:1aaa9921225>):sp1},{**0:aa},{***:aa2},{(<**1:>(Msp1)):sp1},
{(<**2:>(Msp2)):sp2},{(<**8:>(Mli)):li},{(<**9:>(Mpp)):pp},{(Mpli):pli}
Service Providers -> ITSP Profile A -> General -> DigitMap:
(<0:18005000000>|<411:18003733411>|<511:18885004636>|1xxxxxxxxxx|
<1>[2-9]xxxxxxxxx|<1aaa>[2-9]xxxxxx|011xx.|(Mipd)|[^*]@@.'@'@@.)
where aaa is your local area code.