I have to add that I do believe a UK phone will work through the cable modem but do know of people in the past connecting to the Swisscom Fixnet network that had to buy a converter to connect to the phoneline (ie. changing cable did not work) so ... your mileage might vary.

Couple that with the power plug/adaptor you'll need and you might find the sub-100 franc phone with caller ID etc to be your best solution....