You'll be making calls with the Vigor2500V in about 15 minutes. By plugging your existing phone into the router, you can make calls using VoIP or your regular PSTN telephone line by dialling #0 before the number.
Calls to other VoIPers are free and you're allocated an SIP address (akin to a Skype ID) so that others can call you, even if they themselves aren't on DrayTek's DrayTel service. Calls to landlines cost 1p per minute, and you're given an 0870 number so people can call you at national rates.
Call quality is good, thanks to the router setting aside bandwidth when you're using the voice facility. This means that you can continue to surf without worrying about compromising the audio quality of your call, an excellent feature. Mike Abolins