The supermarket chain is hoping to capitalise on Ofcom predictions that UK VoIP users will swell from 500,000 to three million by the end of 2007.
Tesco customers can make calls to other Tesco internet phone users for free, and call other numbers around the world for as little as 2p per minute.
Calls to UK landlines are charged at 2p per minute, along with a selection of international destinations. Calls to UK mobile numbers are charged at 10p per minute, with the exception of Hutchison 3G which costs 25p per minute.
Calls to other international destinations, and services such as 0845 numbers, vary depending on the country and whether users are dialling a landline or a mobile. Most are between 10p and 30p per minute, according to Tesco.
Unlike most traditional phone lines, the Tesco system operates on a pay-as-you-go basis and customers can buy credit online or with vouchers purchased from any Tesco store.
Tesco also offers a range of products for use with the system, including an internet phone adapter that allows users to connect a regular phone to a network for making VoIP calls.
The company is also offering three traditional-looking handsets that plug into a PC, one of which is cordless, and a headset.
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