Abstract: A routinable clock circuit for use in an automatic identification of outward dialing (AIOD) system. The clock circuit consists of asynchronous receive and transmit portions connected and utilized in such a manner as to permit a central processing unit to routine both portions in conjunction with one another to determine whether a fault condition exists. Should such a fault condition exist, the circuitry can be used to determine in which portion the fault lies and to further localize the fault to a functional area within the particular portion of the clock circuit. The clock circuit normally functions to drive logic circuitry for transmitting and receiving data consisting of information associated with calls initiated at a remotely located PABX.

Abstract: A data synchronization circuit for use in an automatic identification of outward dialing system (AIOD). The present invention automatically synchronizes streams of binary data sent as lengthy messages between a private automatic branch exchange (PABX) and a telephone switching center. The binary information transmitted to the switching center consists of the calling subscriber's identity within the PABX and the identity of the trunk circuit connecting the PABX to switching center. This information is transmitted in two-out-of-five code. Synchronization is provided by controlling the output of an included clock in response to received binary state changes.