Abstract: An optical fiber cutter/coating material remover apparatus includes an optical fiber cutter unit and a coating material remover unit, the apparatus being configured such that the end portion of the multi-core optical fiber is cut while the optical fiber cutter unit is apart from the coating material remover unit, the cut end portion of the multi-core optical fiber is inserted into the coating material remover unit by sliding the optical fiber cutter unit or the coating material remover unit so that the optical fiber cutter unit and the coating material remover unit are in contact with each other, and then the coating material is removed by sliding the optical fiber cutter unit or the coating material remover unit so that the optical fiber cutter unit is apart from the coating material remover unit.

Abstract: A plastic optical fiber end surfaces processing method is disclosed which allows formation of not only a convex semi-spherical surface but also of an arbitrary profile such as a concave semi-spherical surface. In addition, an apparatus for use in the method, a cutter for the method, and a plastic optical fiber connection method are disclosed. At least the core portion of the end surface of a plastic optical fiber is cut into a semi-spherical surface by a semi-circular cutter, which is of a convex or a concave shape. This cutter is inserted into a through-hole of a holder and rotates therein. The plastic optical fiber is inserted into the through-hole of this holder, and end surface processing is effected by the rotating cutter.

Abstract: The present invention provides a temperature sensitive paint for low-temperature use which shows durability at low temperatures, has a high light emission intensity, and makes it possible to perform precise temperature measurements of surface temperature fields by applying the paint to the surface of an object and measuring the light emission even in cases where the measurement distance is long in, for example, a large cryogenic wind tunnel or the like. The temperature sensitive paint for low-temperature use contains a ruthenium complex having a high light emission intensity as a temperature sensitive luminophore, a urethane type polymer as a binder, and an alcohol organic solvent as a solvent. Use of an alcohol organic solvent makes it possible to dissolve a temperature sensitive luminophore at a high solubility and to increase the light emission intensity by raising the temperature sensitive luminophore concentration in the coating film, so that more precise temperature measurements can be performed.

Abstract: Disclosed are a plastic optical fiber end surface processing method which allows formation of not only a convex semi-spherical surface but also of an arbitrary profile such as a concave semi-spherical surface, an apparatus for use in the method, a cutter for the method, and a plastic optical fiber connection method. At least the core portion of the end surface of a plastic optical fiber is cut into a semi-spherical surface by a semi-circular cutter, which is of a convex or a concave shape. This cutter is inserted into a through-hole of a holder and rotates therein. The plastic optical fiber is inserted into the through-hole of this holder, and end surface processing is effected by means of the rotating cutter.

Abstract: A call meter signal receiver is provided for a subscriber's private metering system operated by a call meter signal sent from a central office. The receiver is operable both by common mode and normal mode signals. The receiver is small sized and can be installed in a central office trunk of private branch exchanger equipment. The call meter signal receiver is composed of a frequency tuned receiver including two buffer circuits, the first one for receiving the common mode and the second one for receiving the normal mode signal. The first buffer circuit is connected to the input side of a hybrid circuit of the COT, and has a high impedance, while the second buffer circuit, for receiving the normal mode signal, is connected to one of the output terminals of the hybrid circuit, and has a high impedance for voice signals.

Abstract: In a calling signal transmitting apparatus, a ring trip equipment, including a ring trip detecting circuit for detecting a ring trip signal in response to an off-hook operation of the telephone set during a signal state of an intermittent ringing signal and a loop detecting circuit for detecting a loop signal in response to an off-hook operation of the telephone set during a nonsignal state of the intermittent ringing signal. Also included are a logical OR gate circuit, for providing, as a status signal, a logical sum of the ring trip signal and the loop signal, and a supervising circuit for supervising the status signal.

Abstract: A communications system for transmitting and receiving data and voice signals simultaneously on 2-wire signal lines, which superposes and extracts high frequency modulated data signals using a high frequency transformer which is coupled to the 2-wire signal line. The transformer has two windings which are short-circuited with respect to high frequency components, but which pass low frequency voice signals between the 2-wire signal line and a low frequency hybrid circuit.

Abstract: A battery feed circuit for a subscriber line includes first and second feed circuit parts, each supplying a constant current to a corresponding subscriber line. The first and second feed circuit parts are provided with at least one of a common mode noise suppressor and a power source noise suppressor. The common mode noise suppressor includes first and second reference voltage output circuits and an intermediate voltage output circuit to produce the voltage between the first and second subscriber lines and superpose the same onto the first and second reference voltages. The power source noise suppressor functions to cancel the power source noise voltage at the output, of the first and second feed circuit parts.