[Glesgie]

Telephone systems are notoriously susceptible to cable faults anywhere in the chain
from the device to the local exchange. I once had a connection that worked fine
except after heavy rain when the cable to the exchange got flooded !

I would try making sure that the TiVo is the only device connected to a phone socket
and if possibly connect it to the Master socket, if you know which one that is.

 

[Glesgie]

When you say "Telephone over IP" what do you mean ?

If you have broadband, you need a microfilter on the connection to the TiVo as if it was
a telephone.

 

[Glesgie]

Have you ever managed to connect your TiVo since you got broadband ?

Some broadband suppliers switch on echo cancellation on their lines
and this will confuse a modem.

 

[Glesgie]

Just another thought, but if you have a friend and/or neighbour who DOESN'T have broadband, you could take your TiVo to them and that would help determine
if it was a line problem, or a TiVo modem problem.

 

[Glesgie]

Have you got an analogue modem on a computer ?

If you have then you can dail the same number as the TiVo and see if that modem will
connect to the ISP. If it does not then you need to talk to you braodband supplier.

I had a similar problem and finally resolved it by going the Terbonet route.
Best decision I ever made.