Payments company Cuscal has launched a trial of a mobile payment system using host card emulation. HCE is a system that allows the consumer's payment card credentials to be stored on servers in a secure location, accessed by cloud-based software.Cuscal's in-house trial will test the proposition that Visa cardholders can use a mobile phone running on Google's Android KitKat operating system as a contactless payment device.The use of host card emulation makes Cuscal's service different from the mobile-based contactless payment services offered by Commonwealth Bank,  as well as those being developed by Westpac and ANZ.The system the banks are using is called a phone-based secure element solution and requires the financial institution to work with handset manufacturers and telecommunications companies to embed the customer's account details in the phone.Cuscal general manager of products and services, Adrian Lovney, said the HCE approach had some advantages. It does not require any additional processes by third parties, unlike the secure element solution which requires the co-operation of third parties.In theory, this means the system can be updated more easily.From a consumer point of view, the transaction at the point of sale proceeds in the same way, whichever technology is used.Lovney said Cuscal had a lot of testing to do to make sure it met Visa standards, followed Google Android protocols and that all mobile handsets could be placed in the right position to be used at the various point-of-sale terminals. Once in place, up to 15 messages between the phone and the reader are needed, said Brian Parker, Cuscal's chief information officer. He said that his early trials over 4G networks have indicated transactions are being validated in 400 milliseconds, or about half a second each.Lovney said Cuscal was aiming to have a consumer launch in the middle of the year.