Abstract: In order to provide a substrate such as an optical preform rod (24) which is suitable for insertion into a tube and which has a transverse cross section that is substantially circular and disposed concentrically about a longitudinal axis of the substrate substantially along its entire length, a force-applying means such as a graphite roller (52) is adapted to be moved incrementally toward an axis of rotation (35) about which the preform rod is turned rototably. Movement is discontinued when there is an indication that the force-applying means has been in continuous engagement with the preform rod for at least a predetermined portion of the periphery of the rod. In a preferred embodiment, the engagement of the force-applying means and the preform rod is discontinued after a predetermined time, whereafter the force-applying means again is moved toward the axis of rotation.

Abstract: In order to provide a substrate such as an optical preform rod (24) which is suitable for insertion into a tube and which has a transverse cross section that is substantially circular and disposed concentrically about a longitudinal axis of the substrate substantially along its entire length, a force-applying member such as a graphite roller (52) is moved incrementally toward an axis of rotation (35) about which the preform rod is turned rotatably. Movement is discontinued when there is an indication that the force-applying member has been in continuous engagement with the preform rod for at least a predetermined portion of the periphery of the rod. In a preferred embodiment, the engagement of the force-applying member and the preform rod is discontinued after a predetermined time whereafter the force-applying member again is moved toward the axis of rotation.

Abstract: In order to provide a substrate such as an optical preform rod (24) which suitable for insertion into a tube and which has a transverse cross section that is substantially circular and disposed concentrically about a longitudinal axis of the substrate substantially along its entire length, a force-applying means such as a graphite roller (52) is adapted to be moved incrementally toward an axis of rotation (35) about which the preform rod is turned rotatably. Movement is discontinued when there is an indication that the force-applying means has been in continuous engagement with the preform rod for at least a predetermined portion of the periphery of the rod. In a preferred embodiment, the engagement of the force-applying means and the preform rod is discontinued after a predetermined time whereafter the force-applying means again is moved toward the axis of rotation.

Abstract: A system for use in a telephone exchange to measure the duration of a telephone call includes an electrical power source from which pulses of constant frequency are applied to first and second pulse generating circuits for generating pulses at selected frequencies representative of a call initial time rate and a call overtime rate, respectively. Each of the pulse generating circuits can be programmed independently to generate pulses at different selected frequencies representative of different call time rates. The pulses from the generating circuits are applied to a plurality of pulse counting circuits through respective pulse count control circuits. At the beginning of a telephone call, one of the pulse counting circuits is seized by associated circuitry of the telephone exchange and the respective count control circuit first passes initial time rate pulses to the counting circuit while blocking overtime rate pulses.