Terminal adapter

A terminal adapter including a transmit/receive control section for controlling telecommunication between a user terminal device connected to the terminal adapter and a user terminal device of another terminal adapter line-connected to the user terminal device through a selected one of particular telecommunication networks respectively provided by a particular common carrier with which a user made a service contract, comprising:

• a memory device for storing at least one table indicating adapter-operating conditions for determining operations of the terminal adapter, in which said adapter-operating conditions includes a plurality of exchange identification numbers respectively specifying particular exchanges respectively provided in the particular telecommunication networks;
• a selector switch connected between a codec connected to a telephone and a first interface connected through a DSU section to a connection port to said transmit/receive control section to establish a line connection between said user terminal device and the user terminal device of said another terminal adapter and connected to an adapter management section to permit a server in a service center to serve as a master and the terminal adapter to serve as a slave;
• said adapter management section accessible to said memory device for causing a download memory area of the toll database system associated with any one of the plurality of particular memory devices to store therein structured toll information delivered from a common carrier when access is made from a toll database system with the intent of delivering the structured toll information,
• said adapter management section connected to the selector switch for converting the downloaded structured toll information into a toll-table form, and preparing or renewing, with use of the structured toll information converted into the toll-table form, the toll table in which structured toll information in respect of the telecommunication networks, respectively provided by a plurality of particular common carriers, are associated with network-utilization conditions and common carrier names or common carrier identification numbers;
• and
• said transmit/receive control section connected to said selector switch for selecting, in response to manual input of a called party's telephone number through the user terminal device, one of the plurality of particular telecommunication networks or a public telecommunication network, and reading out, when one of the particular telecommunication networks is selected, the exchange identification number corresponding to the selected particular telecommunication network from the at least one table stored in the memory device and for delivering the same.