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Telephone Connection - Organizing Telephone Exchanges

.. Computers work

Telephone Connection

The electronic computer undertakes two basic tasks in the field of telephone connection. It may organize the work of telephone exchanges by receiving a large amount of data coming from various sources, sorting and managing it, and then directing each of them in the correct path, or the computer may recognize the destination of each telephone call and prepare the best path for it from the source to the destination, via a number of exchanges and wire lines or via satellites. The vital importance of the telephone field in our contemporary life is not hidden, especially since the telephone system is no longer limited to transmitting calls, but has become used to transmit various types of data.

Organizing Telephone Exchanges

When the telephone dial is turned or its contacts are pressed, according to the number to be called, the electrical signals resulting from this process determine the path that the call will take through traditional telephone exchanges, as the wire connections in these exchanges are prepared in advance to connect subscribers to each other. Whether the requested number is local or not, the connection is made according to the wire connections in the relevant exchanges.

The switchboards that are organized by electronic computers are faster in performance than traditional switchboards and have fewer wire connections. The computer stores what should be done in the event of a signal from a subscriber and constantly monitors the status of the switchboard and the lines operating in it, allocating new lines as needed.

The telephone line is considered a worker in several cases. A subscriber may pick up the receiver of his telephone in preparation for dialing a certain number, or he may dial a certain number, or the line may be busy with an ongoing call, or the telephone may be ringing with a call, or the subscriber may have finished his call and put his receiver back but his line has not yet been closed. When a telephone call request arrives at the computer, the computer interprets the request code and returns the information
Computer-mediated telephone connection system. The signals arrive either from remote telex devices or from typewriters in the same building. Then the texts are first printed in the source office and reviewed and modified as necessary, then stored with their counterparts and sent all at once at the appropriate time to save costs. In addition, each signal carries numbers that symbolize its destination stored in it to choose the required connection. The computer quickly browses the lines. If it finds the required line busy or signals the caller with a busy signal. Also, when the computer receives a call cancellation signal that was on a specific line, it frees that line from its connections and deletes the call from its memo and prepares to receive another call.

These systems are designed to match their capacity to handle incoming calls with the number of lines connected to the switchboard. If the speed of incoming calls to the switchboard exceeds the speed of its handling, the incoming requests are arranged in a queue and no new requests are accepted until the queue is shortened. Fortunately, the probability of incoming requests at the same time on all lines connected to the switchboard is very small, so the system is designed on the basis of handling calls on a small portion of the total lines connected to the switchboard. However, this portion must be estimated accurately, based on mathematical probability theories.

The importance of the switchboard's operating speed for its good performance is obvious. If electromechanical relays were initially used to connect lines together, they were followed by feather relays, which are small circuit breakers with spring steel feathers mounted in sealed glass tubes. If affected by an external magnetic field, they bend and an electrical short circuit occurs in a period not exceeding two thousandths of a second. If the magnetic field is removed, the short circuit is broken within a thousandth of a second. Modern switches rely on semiconductor media to connect and disconnect circuits in a period not exceeding a few millionths of a second.