How do I set-up my computer to dial Fast4? When you have completed your sign-up you would have created a username and password, and we will give you a telephone number for your computer to dial into. The dialup subscription number you should use is 0808 9916234 and will allow free-phone access on your BT landline. Simply make a new connection through 'Dial-up Networking' on your PC and you will have immediate Internet access. If you have any problems you can call Customer Services on 0871 424 0185.