Tieline VIA User Manual page 6

Step 4. Plug the Via, Laptop and External speaker to
the 240 volt power (optional if using battery only)
The power plug for Via 240 volt connection
Using the cables supplied, plug the Via, Laptop and External speaker to the 240 volt power
box and connect to the power outlet. Then you can switch the power on.
(Of course if it is a remote OB using battery in all 3 units this step will not be required.)