ISDN TERMINAL ADAPTOR

PURPOSE:To always attain proper and inexpensive exchange service by providing a data compacting means to the adaptor so as to decide automatically a line exchange service or a packet exchange service depending on quantity of data. CONSTITUTION:The ISDN terminal adaptor 1 receiving a call request from a data terminal equipment 2 connected to the adaptor 1 makes a call by line exchange service or packet exchange service. Transmission data of the equipment 2 are compressed by a data compacting section 5 and the compressed data are stored in a memory 6, and a central processing unit section 10 monitors transmission data quantity and compares it with a predetermined data quantity. When the transmission data quantity is more than the predetermined data quantity, the line exchange service is selected and when the transmission data quantity is less than the predetermined data quantity, the packet exchange service is selected. Then it is discriminated that the present call is made by the line exchange service or the packet exchange service, and when the result of discrimination indicates that the exchange service differs from the selected exchange service, an exchange call set at present is interrupted and the selected exchange call is changed again and then the data are sent to the same communication opposite party.