QuoteThe tipringvoltage is at 0V.
The tipringvoltage is the voltage coming in from the British Telecom line. If it is 0v then the line is not connected to the OBi. I'm assuming that a phone plugged into the wall socket works ok.
You need a connector or cable that connects pins 2 and 5 of the UK style 431A wall socket to pins 2 and 3 of the US style RJ11 plug that connects into the OBi.