Does Vestalink mean setting up a sub-account under your main account or a totally new account with a different phone number? If it's possible, a sub-account is the way to go. You would have 2 extensions for the same phone number. I'm not familiar with Vestalink, so I don't know if this can be done.
The following is how to use OBi100#1 and the OBiTalk network to make and receive calls from OBi100#2.
In OBi100#2
Physical Interfaces -> Phone Port
Add the following to the beginning of the OutboundCallRoute:
{(<200111111*>(Msp1)):pp},
200111111 is the OBi number of OBi100#1
This will route outbound calls from OBi100#2 to OBi100#1 using the OBiTalk network.
In OBi100#1
Voice Services -> OBiTalk Service
Add the following to the beginning of the InboundCallRoute:
{200222222>(Msp1):sp1},
200222222 is the OBi number of OBi100#2
This will bridge outbound calls from OBi100#2 to SP1
Voice Services -> SP1 Service -> X_InboundCallRoute
The default is: ph
Replace it with: {ph,pp(200222222)}
200222222 is the OBi number of OBi100#2
This will route inbound calls on SP1 to the Phone Port and OBi100#2.
Disclaimer: I did not test any of the above, so there might be errors.
