Barrel Connector for TS1

Can anyone tell me how the 2GIG‐AC2‐PLUG is connected to a TS1? My TS1 has a serial number greater than 1405XXXXXXXXXXXX which I understand is required to use the barrel connector. Thanks.

The barrel plug connector is not required, you can still connect to the screw terminals, but when looking at an open TS1, right side up, the barrel plug is behind the circuit board at the bottom left corner.