Abstract: A thermally controlled equipment cabinet for telephone systems has a gas-tight, sealed compartment for mounting sensitive active electronic components and has jacket 20 partially encompassing at least three sides of the sealed compartment. The sealed compartment utilizes either forced or natural convection to dissipate the heat generated by the components to the surrounding air. The heat is then dissipated to the ambient air through a highly heat-conductive corrugated roof and side panels. The jacket provides a cooling air passage around the sealed compartment and over the corrugated roof removing heat thereof. Nonsensitive passive components, mounted in the cooling air passage near the air inlet of the jacket, provide protrusions in the cooling air passage causing a slightly turbulent air flow in the passage thereby enhancing heat transfer. Storage batteries, such as used in telephone systems, are mounted within the cooling air passage near the air exhaust of the jacket.

Abstract: In order to protect electrical and fiber optic cables in a central telephone office terminal equipment frame, the cables are controlled and managed so as to be releasably retained in a service loop within a fiber management panel. The releasable retention is performed by a stretched extension spring selected, dimensioned and stretched in such a manner with respect to the diameter of the cables that each cable can be gently but firmly retained when pressed into the gap between adjacent coils. The retention spring permits emergency release of the cable in the event of mishandling of the equipment by service personnel.

Abstract: A locking handle assembly used in combination with printed wiring boards and the like has camming portions which cooperate with a rod on the housing for the boards to act as a lever thereby positively seating and unseating its associated board within the housing. The handle assembly is provided with locking serrations. The serrations are positioned along radial curves so the handle is allowed to undertravel or overtravel, thereby compensating for tolerance buildup which could prevent proper seating of printed wiring assembly. An electrostatic discharge clip of the handle assembly engages the rod on the housing to ground the same and thereby prevent static electricity from the operator from producing an adverse effect on the electronic components.

Abstract: A control system for a slide centrifuge includes a ratio checking circuit which produces a signal when the ratio between the light passing through the slide and the rate of change of this light passes through a predetermined critical value. When this ratio passes through the critical valve, spinning is stopped. This effectively stops spinning when the rate of reduction of blood cell density on the slide slows, thereby producing better slides for clinical analysis.

Abstract: A control system for a slide centrifuge includes a ratio checking circuit which produces a signal when the ratio between the light passing through the slide and the rate of change of this light passes through a predetermined critical value. When this ratio passes through the critical value, spinning is stopped. This effectively stops spinning when the rate of reduction of blood cell density on the slide slows, thereby producing better slides for clinical analysis.

Abstract: In the preparation of blood films for microscopic examination a slide spins in a centrifuge for a time which is a function of the red blood cell concentration of the blood. A drive circuit controls the time of spinning of a slide centrifuge. A variable control for the centrifuge motor includes a manual adjustment which is adjustable across a scale labeled as a function of the percent hematocrit of the blood.