Abstract: A keyboard arrangement, such as for a computer or the like, has a number of keys arranged in rows and columns. The keys of each row are associated with a respective conductor and the keys of each column are associated with a respective conductor. Each key, when depressed, interconnects the two conductors. An interrogator is provided to interrogate the rows respectively by transmitting pulses to the rows and to interrogate the columns, to determine the presence of a transmitted pulse. The interrogator is adapted to interrogate the rows in a random or quasi-random order during successive cycles of operation.