Data communication apparatus with interrupt completion detecting

摘要

When an interrupt completion detecting unit detects completion of an interrupt processing, a hooking unit executes hooking automatically. A busy tone detecting unit judges whether or not a station of a suspended telephone communication has been holding the telephone circuit. If not, a call is directed to the suspended station on the basis of stored information on its dialing number. At the same time as the hooking is executed, an on-hook judging unit judges whether or not a handset at the own station is in an on-hook state. If it is on the hook, a predetermined processing for urging an operator to lift the handset is executed. This processing selectively causes ringing of a bell incorporated in a telephone unit or of a buzzer, or indication by a display unit or a lamp. With the above procedure, the telephone communication with the suspended station can automatically be restored in accordance with the situations at the suspended and own stations.