Abstract: The present invention relates to an analysis device, for use in a transit exchange for transmission of asynchronous data signals with known character structure and known nominal signalling rate. The character structure comprises a start pulse and a number of data pulses which are sampled in the exchange by means of sampling pulses in synchronism with clock pulses from a clock pulse source several times per data pulse for the establishment of the binary informational content of the data signals. The device includes means through the aid of which a summation is made of the clock pulse occurring during a data pulse with indication signals being delivered at specific clock pulse positions within the data pulse.