PURPOSE: To warrant communication satisfying a permissible delay time by transferring the communication area to a communication area unable to send information with low priority when the transmission of information with high priority is disturbed by the information of low priority.

CONSTITUTION: When a cell in a cell frame arrives via a transmission line 1, a cell reception section 3 receives it and when the reception destination of the cell is its own node address, the information is transferred to a reception buffer 6, in which the information is tentatively stored. Thus, the information stored in the reception buffer 6 is read by a terminal adaptor 8 and sent to a relevant terminal equipment 9 as user information. Simultaneously, when a reset cell with a different level is generated, a node generating the reset cell of a low level is transited to a low level clip waiting state and when a reset cell of a high level is received, the level is not clipped and the state transits to the normal state of a high level.