Abstract: The invention is to offer a technology with which a call process, a band setting process in particular, from a unit of terminal equipment to a network can be effectively performed, in relation to a communication system in which a communication band necessary for a unit of terminal equipment is secured by transmitting a SETUP message to a network from the terminal equipment as in the case of a call procedure in B-ISDN, etc. In the communication control of the terminal equipment connected to the network, when a call is made if the securing of a band in the network is impossible, the call is cut off, but if the band area in the network is insufficient for an initial band value stored in a SETUP message, a revised band value is produced by subtracting a certain value from the initial band value, and a SETUP message with the revised band value is retransmitted to the network.