What's up with T-Mobile UK? First T-Mobile banned instant messaging and VoIP, as I wrote about last year. And now T-Mobile UK is at it again blocking Truphone, a mobile VoIP operator. Apparently, T-Mobile is blocking calls in a dispute over interconnection fees. When they attempt to dial, T-Mobile customers get a recorded message saying they must have misdialed.

The reason that T-Mobile claims it is not connecting the calls is that the termination rate Truphone wants to charge T-mobile is roughly the same that it pays the other mobile network operators, while Truphone has no mobile network to support and maintain.

"Other operators have invested huge amounts of money into their networks," T-Mobile corporate communications head Simon Marks said. "Truphone has no network to maintain."

UK telecom regulator Ofcom requires phone companies to interconnect, strengthening Truphone claim that T-Mobile is in breach of Ofcom rules by refusing to accept its rates. However, its rates are only reasonable if Truphone is classified as a mobile operator. According to Techworld, Ofcom's rules state that operators are allowed to charge for interconnection to their numbers, and says these fees should be "fair and reasonable" and "transparent". However, Ofcom only states they apply to mobile networks, leaving a possibility for mobile operators to discriminate against those they regard as not being "real" mobile operators.

Thus, it seems likely Ofcom will be have to rule on the whether Truphone is classified as a mobile operator.