well I got a ELSA 56K Internet external modem and it works fine dialing on NTLWorld free service.I use kppp, pap auth.I dont know what UKLinux.net uses but check your modem cable.Some have 4 wires some have 2. Mine wouldn't work on the one with 4 wires and kppp used to start dialing and then die with no-dial tone detected.
I use kppp with UKLinux.net and an external 56K modem with no problems. In kppp set up try the modem commands button which IIRC will check out the basic settings and working of the modem.
Ian
Ian Thompson-Bell
The Technology Partnership plc Melbourn Science Park Melbourn Herts SG8 6EE United Kingdom
Tel: +44 1763 262626 Fax: +44 1763 261582
mailto:itb@techprt.co.uk