Abstract: An apparatus includes a shaft, an expandable dilator, and at least one ventilation pathway. The shaft defines a longitudinal axis and includes a distal and proximal ends with at least one shaft lumen. The expandable dilator includes body with its own proximal and distal ends. The body is configured to transition between a contracted state and an expanded state. The body is configured to dilate a Eustachian tube of a patient in the expanded state. The at least one ventilation pathway is configured to provide ventilation from the distal end of the body to the proximal end of the body when the body is in the expanded state. In some examples, the ventilation pathway includes a set of transversely oriented vent openings formed through the shaft. In some other examples, the ventilation pathway includes a space defined between one or more radially outwardly protruding features of the expandable dilator.

Abstract: Information to be written in the form of magnetic flux reversals on the surface of a disk or diskette is applied in serial fashion to a first shift registor. The parallel outputs of the shift register address a PROM. The PROM output is applied to a second shift register in the form of clock and data bits to be written on the disk or diskette magnetic surface. Control signals applied to the PROM address terminals select the mode, FM or MFM, the address mark or if precompensation is required.