Abstract: An electro-mechanical filter comprises an inlet electro-mechanical transducer (12) an outlet electro-mechanical transducer (14) and a mechanical filter constituted by a series connection of resonator bars (1 to 11) which are interconnected by couplers (20 to 29). The bars are half a wavelength long at the central frequency of the pass-band while the couplers are one-quarter of a wavelength long. Instead of being connected to the ends of the bars, the couplers are connected to recessed stepped flats (40) located near the ends of the bars. The positions of the flats (40) are determined to be close to nodes in the first few orders of partials in bending mode vibration of the bars. This has the effect of greatly attenuating the excitation of such parasitic bending modes of vibration. Clearance to enable the couplers to reach the flat (40) is provided by a more deeply stepped positioned flat (41) extending to the end of the rod. Such filters may be used in terminals for analogue transmission systems.