Coca-Cola said Wednesday it will invest $100 million with a British communications and information technology firm to make "smart" vending machines that will tell bottlers when they're empty and allow for cashless purchases.The five-year deal with London-based Marconi PLC is designed to help Coke bottlers improve inventory management for more than 500,000 machines worldwide.The technology will allow distributors to know such things as when a machine is empty and which brands are selling best, Coke spokesman Trey Paris said.Ultimately, the technology will allow for cashless vending -- for example, allowing a customer to buy a beverage with a credit or debit card or by charging it to a cellular phone account, Paris said.In October, former Coke Chairman M. Douglas Ivester angered many consumers when he disclosed that the company was studying ways to remotely raise and lower vending machine prices depending on weather conditions.Paris repeated Coke's earlier assertion that the technology will not be used to increase prices."We would never apply it in ways that would take unfair advantage of consumers," he said.