Abstract: A passive fiber optic device and optical fiber connected to it are packaged in a solid block of a bismuth containing fusible alloy. The alloy exhibits appreciable expansion on solidification, negligible dimensional change after solidification, and a low thermal expansion coefficient. Coupled with its low melting point and glass wetting ability, the alloy is uniquely adapted for forming a hermetic seal with glass. By molding as a solid block, the packaging operation is rendered simple and rapid.

Abstract: A circuit which is particularly adapted for reconstructing fixed time duration dialing pulses in a telephone communications system while rejecting spurious pulses of less than a selected pulse duration. The circuit utilizes two coupling networks having integrated outputs of opposite polarity which are summed after passing through two separate switching amplifiers. The summed outputs are fed through a third switching amplifier having a hysteresis characteristic so that it switches only when both outputs have switched to the same polarity.

Abstract: In a telephone system supervision is provided for, between a local terminal typically associated with a telephone switching facility and a remote key telephone terminal. A data link between the terminals includes a two wire transmission line terminated with hybrid circuitry. The hybrids provide full duplex operation. Electronic circuitry, in the local and remote terminals, operates to provide continuous two way transmission of supervisory data by means of diphase signals. A coded diphase signal transmitted from the local terminal has a baud rate twice that of the conventional diphase signal transmitted back from the remote terminal. This allows simple receiver sync extraction circuitry in both the remote and local terminals. The length of transmission line permissible between terminals is limited by a maximum permissible one way delay of half the period of the maximum baud rate.