Abstract: A piezoelectric speaker includes a casing and cover member having a transverse wall extending therebetween which forms a sound transmission channel having a spiral curved or double reverse bend shape and being of substantially continuously increasing cross sectional area between an inlet portion of said channel and an outlet opening to atmosphere. A driver element comprising a diaphragm formed of fiber reinforced epoxy, polyester or ABS resin has a piezoelectric ceramic disk secured thereto and supported in a recess formed on the cover member. A sound transmission opening in the cover member communicates with the inlet portion of the sound transmission channel. The diaphragm may be formed integral with the cover member. The speaker has the capability of expanding the frequency band width of audible sound at relatively high sound pressure levels.

Abstract: A passive telephone line monitor is provided for keeping a log of telephone line activity, both incoming and outgoing, with a microcomputer (MCU) controlled by an onboard program read only memory (ROM) working with 64K bytes of random access memory (RAM) divided into 32 byte caches allowing for up to 2,000 phone call registers depending upon utilization of available space. One hundred Alpha Directory numbers can be stored from its keyboard for personalized caller identification. Upon power application, memory, input devices and registers are initialized, and time and date are entered from the monitor keypad. The microcomputer, an interrupt controlled device, detects monitor keyboard interrupt and displays the data on a liquid crystal display, and upon completion of date and time entry, the MCU clears all interrupt flags and displays current date and clock.

Abstract: A noise frequency and vibration absorbing mount is provided for microphones, particularly highly directional sound-gathering microphones, that, while achieving highly efficient reduction in the transmission of noise frequencies and vibrations, maintains directional alignment with the camcorder or camera, binoculars, rifle scope or whatever other equipment it may be mounted on regardless of directional change movements imposed on equipment mounting the microphone. The noise frequency, vibration absorbing and directional change stabilizing mount includes a hollow accordion pleated resilient material four walled enclosure fastened at its bottom to a mounting plate having two inside to outside small air flow dampening openings therein.