Tagg points out that T-Mobile refuses to interconnect with operators offering VoIP as a matter of policy however T-Online Ventures, the venture capital arm of T-Mobile's parent company Deutsche Telekom, has just invested in VoIP provider Jajah; T-Mobile connects with BT Fusion, a VoIP service; and T-Mobile has also announced a trial of a VoIP service in USA and Germany.
The other four UK major mobile network operators - 3, O2, Orange and Vodafone - all interconnect with Truphone, leaving T-Mobile isolated on this issue.
Tagg, said: "This affects every new entrant into mobile telecommunications because the only company that can facilitate interconnection with T-Mobile is T-Mobile. To refuse is therefore an abuse of its position. It amounts to T-Mobile being able to veto a new entrant into the market. This would put telephony back 100 years, to a time when interconnections were not assured."
"If I were a shareholder I'd be asking some tough questions about whether T-Mobile is prepared for the internet age. It looks like a company in chaos with no coherent strategy for VoIP: it is both resisting VoIP and buying it, and at the same time running ads saying it sets the internet free. Maybe the left hand simply doesn't know what the right hand is doing."
"T-Mobile's move is the most aggresive act but it isn't alone in trying to find ways to slow down mobile VoIP. Vodafone and Orange tested one way by removing internet telephony from their branded Nokia N95 handsets without telling their customers, and Vodafone is planning to charge more for VoIP traffic than for web traffic on its new mobile web service."
"T-Mobile will argue that it is not 'blocking' Truphone but is merely negotiating on price. T-Mobile receives 35p per minute from its customers but is offering only 0.21p per minute to Truphone even when Truphone's costs are 9p per minute to terminate the call. T-Mobile is blocking our numbers unless we accept this loss-making offer and, since T-Mobile is the only company that can route calls from its customers it has a complete veto on the Truphone service."
T-Mobile's current adverts display the slogan "Setting the internet free".