Abstract: A valve for regulating the flow of a liquid, for example in liquid chromatography, comprises a valve seat and a valve ball which are made of electrically conductive ceramic or glass material. Due to the electric conductivity, electrostatic charging is avoided which would otherwise attract dirt particles and lead to contamination and leakage of the valve. The valve is chemically inert and is not corroded by the solvents typically used in analytical chemistry.

Abstract: A method for controlling a signalling procedure in communication terminal equipment such that initialization and control of the signalling procedure or of subscriber performance features is achieved with a minimum of additional, special keys. First procedure control information that defines a signalling sub-procedure is formed after every activation of the communication terminal equipment and before every branching of the signalling procedure into a plurality of signalling sub-procedures. Procedure control information is communicated to a display device for the purpose of visualization of at least one procedure control information. Upon actuation of a sequence key in the communication terminal equipment, further procedure control information defining a further signalling sub-procedure is formed and is communicated to the display device.