A revival in tax travel over the last half of 2010 has reversed a decline in turnover for the Cabcharge payment system. Cabcharge yesterday said revenue increased 3.5 per cent, to $537 million, in the December 2010 half year, following 18 months of decline.A renewal of the firm's core payments products is also leading to a shift in payments patterns. Cabcharge said there was growth of eight per cent in turnover on Cabcharge accounts and a corresponding decline in payments on American Express and Diners Club cards. Turnover on bank-issued Eftpos cards increased three per cent.Cabcharge maintained its merchant fee at 9.2 per cent, a margin that a range of competitors have attempted to undercut but found difficult to do.In September 2010, Cabcharge agreed to pay a $15 million fine for repeatedly misusing its market power over the last six years.As a result of this fine, Cabcharge's net profit fell 45 per cent, to $16.4 million, over the half.