Analogue 'phone connected to EX3301-T0 - no ringback tone

perdrix

I have an EX3301-T0 router with an analog DECT base station connected to the 1st analogue 'phone port. The router is supplied by Voneus (my ISP) and connects to a VOIP server at voip123.co.uk.

Often, but not always, when a call connects I hear no ringback tone, just silence until the other end answers the 'phone. Voneus technical support claim the problem is my 'phone, but after skimming the VOIP protocols I don't believe that can possibly be correct.

Is this a known issue with these routers? If not what can the problem be.

Thank you, David