Abstract: Telephone calls from an extension (32) on a private branch exchange (PBX) (14) are directed by an automatic telephone dialer (12a) to an outside line (18) of a local operating company or to a dedicated line (22) connected to the facilities of a specialized common carrier. The dialer is connected to an extension line (36) simply as another extension. A call from an extension (32) requesting an outside line is directed to the extension occupied by the dialer (12a), and a ring detector (40) detects the resultant ringing signal and alerts a controller (44). The controller sends a dial tone to the calling extension (32) and records the resultant dialed digits. It then momentarily interrupts its off-hook signal to cause the PBX to place the calling station (32) on hold and dials the appropriate destination. Once the dial has been replaced, it "hangs up," causing the PBX to connect the calling extension (32) to the destination that the automatic dialer has called.

Abstract: A videotex system employs a subscriber unit (22) at a remote location such as a user's home. The subscriber unit (22) employs the user's telephone tone dial (26) for transmission to a communications module at a central location and uses the user's television set (24) for display of information received as frequency-shift-keying signals by the user's telephone (20). At the central location, the system employs a transmission memory (16) containing the currently desired display, and a microprocessor circuit (28) reads the contents of the transmission memory (16) to send it by FSK signals to the remote location. The information contained in the transmission memory (16) comes from a host computer, and an antiquity memory (50) having locations corresponding to those of the transmission memory (16) has its associated location reset whenever a transmission-memory location is written.

Abstract: An automatic dialer for controlling access to a long-distance telephone network. The automatic dialer includes a read/write memory. Each time the user attempts to call through the network a telephone number inaccessible via the network, an entry representing the area code and/or exchange of that telephone number is made in the memory. Prior to calling the network, the dialer compares the destination telephone number with the entries in the memory; the call is placed via the network only if the area code and exchange of the destination number do not match any of the entries. The entries in the memory are ordered according to recency of attempts by the user to access a telephone number within the groups of telephone numbers represented by the entries; when the memory is filled, the oldest entry is deleted to make room for the newest entry.