Patent ID: 6983152

Claim:
A portable telephone system including a base station and a mobile station which communicate with each other by using one time divisional time slot including a high speed channel and a low speed channel, wherein a first communication requiring said high speed channel by a first calling party from said base station to said mobile station and a second communication not requiring said high speed channel by a second party from said base station to said mobile station are carried out simultaneously by using said high speed channel and said low speed channel, respectively, said base station comprising: means determining whether or not said high speed channel is empty, when a new service is requested from said base station to said mobile station using said low speed channel; means assigning said new service to said high speed channel, when said high speed channel is empty; means determining whether or not said low speed channel is empty, when said high speed channel is not empty; means determining whether said new service is related to a first communication which requires said high speed channel or a second communication not requiring said high speed channel, when said low speed channel is empty; and means assigning said new service to said low speed channel, when said new service is related to said second communication.