3Com V3000 ATA Ringing on UK Phones

I've been configuring a 3Com V3000 VOIP PABX. If you want to connect a UK spec phone you need to ensure you use a "PSTN full master". "PABX Masters" or "Secondary adapters" will not allow the phone to ring.





A UK PSTN Full Master contains a capacitor, resistor and spark suppressor. If you use anything other than a PSTN Master you can use the phone to make calls but it will not ring.

There are many different PSTN Masters available with different pinouts. I have sucessfully tested the following Krone part:-

Krone P/N : 6536/1/601/11