subscriber according to the invention subscriber units may communicate unimpeded until an event is detected for example the expiration of a predetermined time interval after detecting this event the controller 114 operates to reduce the coding signal 108 so as to intentionally degrade the quality and or intelligibility of the information signal additionally the coding procedures type may be altered such as by adapting from 9 6 kbs sbc to 2 4 kbs lpc which would reduce the intelligibility or quality of the message in this way the subscribers are encouraged to terminate the communication as the transmitted information signals gradually become more difficult to understand thus abrupt automatic termination of calls is avoided in favor of a gradual quality degradation which encourages the subscribers to voluntarily wind up the communication accordingly communication resources become available for use by other subscribers while the existing practice of re requesting access to the communication resources is reduced since subscribers will tend to complete their message albeit at reduced intelligibility or quality rather than re dial to access the system optionally certain subscribers executives or other high level officials may operate within the communication system without having their communications impededed in any way i e without intelligibility or quality reduction such subscribers are contemplated as being permitted to communicate indefinitely and therefore are encouraged to terminate their communications in the preferred embodiment of the present invention the event detected to trigger intelligibility or quality reduction comprises the expiration of a predetermined time interval according to the invention the subscribers may communicate unimpeded i e a full quality information signal for this time interval which is determined by the controller 114 using any.