| 摘要 |
PURPOSE: A collect call method using DID(Direct Inward Dialing) in a simple private exchange is provided to use a collect call without the necessity of requesting a collect call line additionally. CONSTITUTION: A simple private exchange(10) consists of a central processing unit(11), a main memory unit(12), an auxiliary memory unit(13), a voice processing unit(14), a switching circuit(15), a trunk processing unit(16) and an extension processing unit(17). The central processing unit(11) controls the overall operations of the simple private exchange(10). The main memory unit(12) stores the program operated by the central processing unit(11). The auxiliary memory unit(13) processes the data processed by the central processing unit(11). The voice processing unit(14) processes the voice signal of a call under the control of the central processing unit(11). The switching circuit(15) executes the switching between the trunk processing unit(16) and the extension processing unit(17) according to the control of the central processing unit(11). The trunk processing unit(16) processes trunk calls through a trunk line. The extension processing part(17) processes extension calls through a telephone.
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