Competition in the market for mobile point-of-sale terminals is heating up, with Mint Wireless entering a sector that is already served by PayPal, Paymate and Commonwealth Bank.In a presentation to investors yesterday, Mint said its forecasts were for A$7 billion of mPOS (mobile point-of-sale) transactions next year, growing to $20 billion by 2017.mPOS terminals are small devices that plug into a smartphone and turn it into a payment terminal.Mint's product is compliant with all the relevant security standards and supports chip and PIN (some products in the market only support outmoded magnetic stripe technology).Last month, Mint signed a deal with the accounting and business software company, MYOB, to integrate Mint's mobile payment system with MYOB software.Under the agreement, Mint will receive a licence fee from MYOB and a proportion of the transaction fees from users of the mobile payment solution incorporated into MYOB's software.