ages follow-on voice calls, with more revenues from additional traffic as a result. Payment Transaction Handler The payment transaction handler provides secure payment services for e-commerce trans- actions on the Internet. The handler manages also the financial aspects of transaction handling in a standardized way, also taking the financial risk. In the grocery case the operator could charge the end user/buyer for her/his purchases together with the telecom bill. VISA is another player in this role. The transaction handling is similar to traditional signalling schemes. However, all communication is IP based. See Figure 4.23. Note that payments can also be arranged through the credit card company instead of e-Pay. Apart from all these communication and content-oriented roles there are in fact other types of role. Telecom Business 1. View time table 2. Order ticket GSM 1 3. Make offer 4. Present offer/ Password request 5. Password reply 6. Payment transaction request 7. Payment transaction confirmation 8. Payment confirmation Train: 9. Confirmation of ticket reservation Time table Mobile and payment Journey planner e-Pay Ticket reservation Your reference Mobile operator # 8364A2 .service network Train company London Paris Today network Departure time 10:45 Arrival time 11:55 One way Credit card Paid via Credit card 1 adult, window seats company network WELCOME Figure 4.23 Payment transactions, example Example 1: The retailer role. The retailers focus on the relationships with the end users: subscriptions, marketing, sales, after-sales, bundling of offerings, customer care and invoicing. They sell handsets and other customer premises equipment in shops. Today this role is often part of the activities of the network operators, but it is sup- posed to become more and more independent. One-stop shopping is often part of the business idea. The TINA-C international body includes this role. The TINA business model from 1999 defines the following business roles: The consumer role. The broker role, which enables other busi