Abstract: In a keyboard housing a housing top with a key pad and a housing bottom with support legs wherein the housing includes a support mat and a multi-layer contact foil set arranged underneath the key pad to be actuated thereby, a metal plate is embedded in a recess formed in the housing bottom below the contact foil set so as to increase weight and rigidity of the housing without the need for special molded housing reinforcement structures, the housing bottom, however, having U-shaped reinforcement web structures with bearing studs at their base areas near the housing bottom and housing legs with bearing holes receiving the bearing studs so as to be pivotally supported thereby, the housing legs having locking grooves and the housing bottom having, between the web structures, engagement tongues with locking ribs for engagement with the locking grooves in the housing legs.

Abstract: A system for the automatic establishment of a shortwave telegraphy signal connection between two transmitter-receiver stations within a frequency range subdivided into several channels. Both stations use their receiver to determine objective measurement values reflecting the transmission conditions over the individual channels. Active and passive channel analysis of the actual quality of the signal transmission is determined at each channel. The transmitter of the calling station is automatically tuned to the channel which corresponds to the best channel quality stored in its memory. A predetermined time after transmitting the call signal, the calling station switches to reception and upon reception of an acknowledgment signal from the counter station automatically begins the message transmitting-and-receiving operation. If after a predetermined time no acknowledgment signal is received, the transmitter automatically switches to the channel stored in its memory with the next best channel quality value.

Abstract: The invention relates to a process for absorbing ozone in water by introducing an ozone-containing gas into a water current streaming downward in an absorber, wherein the ozone-containing gas is introduced into the water current in the form of bubbles at the upper end of the absorber and subsequently conveyed downward to the absorber outlet in a direction opposed to its ascending direction.

Abstract: A push-button rotary switch having a switching mechanism including a pair of independent actuators having linear movement into contact with the teeth of a switch position selector ratchet wheel mounted at the center of a rotatable switch-positioning indicator, with the actuators adapted to alternately engage certain of the ratchet teeth so as to rotate the switch-positioning indicator step by step in either direction into different switching positions.