A networked system through which funds are transferred electronically from the customer's account to the retailer's account, usually involving some sort of credit or debit card. Developed in the mid-1980s, this has become indispensable both for retailers and customers in the sale and purchase of goods and services. For example, these systems are linked to epos (Electronic Point Of Sale) systems that record the goods sold by reading the barcodes on the goods. This enables management information to be transmitted to help with in-store merchandising, rapid replenishment of goods that are selling fast, as well as overall inventory and cash flow control. Retailing has become much more efficient as a result of these systems. It has also helped marketers analyse how and what each customer spends, on what and with what frequency, and where.