Abstract: The present invention provides a down light include a thermally-conductive main body, and a substrate which is mounted on this main body through a plurality of screw, has slits which are formed on straight lines connecting the screw with each other in directions orthogonal to the straight lines, and has a plurality of LEDs arranged thereon.

Abstract: A reflector built in a down light includes a plurality of floodlight openings respectively exposing a plurality of light-emitting elements to a front surface side, a plurality of radial partition walls which respectively partition and surround these floodlight openings, and an inner circumferential partition wall. Each of the partition walls has a ridge line, and the reflector includes a plurality of reflection concave surfaces each which open and widen from a respective one of the plurality of floodlight openings towards ridge lines of the plurality of partition walls which respectively surround the plurality of floodlight openings. The plurality of radial partition walls extend from the center of the reflector towards the outer circumference, and the inner circumferential partition wall is located between the center and the outer circumference.

Abstract: Between narrow band radio transmitting and receiving apparatuses, method and apparatus for shortening the starting failure time upon start of transmission are disclosed.By start of transmission at the transmission side, a DTMF signal at 697 Hz to 1633 Hz is outputted from a DTMF generator, and it is changed over to a DTMF signal at 1/10 frequency 0.02 sec later and outputted.A DTMF receiver at the reception side, when receiving a DTMF signal at 697 Hz to 1633 Hz, cancels the output mute circuit to set in service state. The DTMF receiver, when no longer receiving DTMF signal as a result of changeover to DTMF signal at 1/10 frequency, waits for an ordinary DTMF signal at 1/10 frequency, and cancels the output mute circuit until the end of transmission after reception thereof.