Contents of module
- Interconnection Part Five
- Interconnection index
- eLearning main Index
Roaming
Interconnection for mobile operators also arises in two areas of the delivery of international calls for origination and termination. One area is roaming where the customer is making calls from outside Hong Kong, the second is connectivity to, and revenue sharing with, the international gateway facility (IGF) operator for customers in Hong Kong to receive or transmit IDD calls.
When a customer roams outside Hong Kong, their handset transmits a signal that is picked up by the appropriate local mobile network and automatically checked against a database of correspondent operators. If a roaming agreement exists, a signal locating the customer is then transmitted using international leased circuit to the customer’s home mobile operator.
Under an Inter-operator Tariff (IOT) system now in place the Visited Public Mobile Network (VPMN) sends the billing information or Call Detail Record (CDR) together with their own charge at an IOT rate to the customer’s network via a clearing house. The customer’s network may add its own mark-up before billing the customer.
Under a previous system of national network tariffs a markup of 15 per cent was an agreed ceiling, but competition leading to subsidies and bundled services has rendered the old system obsolete.
This raises a serious problem for customers since they are facing a situation where each mobile operator can lay the blame for high roaming charges onto the IOT rates charged by the foreign operator, a situation not very far removed from the traditional accounting system between international carriers. In 2000 the European Commission ordered an inquiry into roaming across Europe for just this reason.