A method and an apparatus allows multiple users to share one or more data communication lines without requiring the users to actively participate in the arbitration. The preferred embodiment comprises an ISDN Port Connection Manager (PCM) for managing the use of each of the individual channels of one or more line ports having ISDN service thereon. The ISDN PCM manages the use of the channels between applications using such distinct access methods as the IBM Virtual Telecommunications Access Method (VTAM), TCP/IP, and Open Systems Interconnect (OSI) access methods. The ISDN PCM determines that an application needs access to an ISDN channel, determines the availability of the ISDN network and sets up the communication between the application and the network if the channel is available. If no channel is available at that time, the ISDN PCM indicates to the application when the channel becomes available so that the application may determine whether it still needs access.