Abstract: When high frequency signals are transmitted to an integrated circuit through a lfine, the line must have a matched terminal resistance located as closely as possible to its end. Every portion of the line without a matched terminal resistance, and each branch of the line, produces disturbing signal reflections. In modern housings of large-scale integrated circuits the terminals are only separated by 0.5 mm, and it becomes increasingly more difficult to connect a resistance as closely as possible to the terminal of the integrated circuit. According to the invention, a field effect transistor (T.sub.R), which functions as a terminal resistance, is located inside the integrated circuit. The value determined by the channel resistance is adjusted by means of a regulated control voltage, so that the effects of operating temperature, changes in the supply voltage and deviations in the integrated circuit caused by manufacturing processes have no effect on the resistance value needed for the line match.

Abstract: A buffer or other communications resource in, e.g., an ATM switch element receives random data which is then used by different data sinks. After the data has been outputted to the data sinks, the communications resource (e.g., the memory locations of the buffer) are released, i.e., labeled as free again. However, a resource which is not marked as free as a result of an error (whether erroneously the data is not retrieved or whether the release procedure is erroneous) remains blocked. To avoid permanent blockage of those memory locations whose contents have been in the buffer so long that they definitely (or at least very likely) should have been called for, information on the time of entry is stored together with the data. All memory locations are checked at regular intervals for the age of their contents. Upon attainment of a predetermined age, the location is labeled as free.