A communication network which can use communication bandwidth effectively. Spreading codes of a first and a second code length are assigned for every communication terminal interfaces connected to the same communication network. The spreading codes of the first code length are used for data communications. The spreading codes of the second code length are used for the control communications between the interfaces and the server. The interfaces and the server receives mixed signals of the data and the control signals. When the received signals are decoded using the spreading code of the first code length, control signal components became equal to or lower than the noise level. When the received signals are decoded using the spreading code of the second code length, data components became equal to or lower than the noise level. Therefore, the interfaces and the server can extract one of these signal components.