Abstract: Standard cells and AAL2 cells are processed by a single AAL terminating unit to reduce whole circuit scale of a radio communication system. An AAL identifying unit 3 determines whether an ATM cell is a standard cell or an AAL2 cell. When the ATM cell is a standard cell, the cell is transferred to the AAL terminating unit 7 as it is when the ATM cell is an AAL2 cell, the cell is assembled and to produce a plurality of ATM cells each of which corresponds to one of the short cells in the AAL2 cell and transferred to the unit 7. The unit 7 determines an AAL type of the ATM cell and processes then according to the AAL type.

Abstract: A communication system which can establish a control link between a radio base station and a switchboard station, without assigning beforehand any representative or proper VPI/VCI to the radio base station which is to be newly established. A switchboard station transmits a cell which includes a link establishment request signal to a newly established radio base station. Therefore, the radio base station can receive the cell, regardless of the VPI/VCI values, because a mask set up unit in the radio base station sets mask approval, beforehand. Further, the radio base station, after receiving the cell which includes a link establishment request signal, stores the VPI/VCI values included in that cell in a down cell header information memory, and transmits a response signal.