PURPOSE: To suppress the overflow of a buffer in an exchange by defining a maximum terminal transmitting speed and maximum burst length from a terminal as reporting values, forecasting the value of the maximum queue from these reporting values and judging possibility to receive a call when the exchange receives the call from the terminal.
CONSTITUTION: When a terminal 41 sets a call 40 to a called party terminal 42, a call setting request 62 is transmitted to an exchange 10-d by using a control channel. When the exchange 10-d receives the call setting request message 62 from the terminal 41, it is checked whether the overflow is not generated in the exchange 10-d or not, and it is judged whether the call 40 can be received or not. When it is judged that the call 40 can be received, a call set receiving message 63 is returned to the terminal 41. Accordingly, in a data transfer phase, since the overflow is not generated at the buffer in the exchange, the data can be prevented form being abandoned.
KAWAKITA KENJI
KASHIO JIRO
