Pipex ADSL Router problems

Recently my Belkin Wireless G Router that had been working stopped
making ADSL connections (to Pipex).

I got my old Speedtouch Modem out of retirement and it all connected
up fine so I presumed it must have been a fault with the Belkin box.

I eventually got round to buying another Wireless ADSL router (a Zoom
ADSL 2/2 + Wireless-G Router + Switch). Having gone through the setup
(and some more detailed checking) it won't recognise the ADSL line and
says it is in Handshake mode.

Seems odd that 2 ADSL routers should exhibit this failure but the USB
Modem doesn't.

Before I take the new one back, any ideas?

TIA

Neil