1. In a scanning radio receiver, including frequency synthesizer means for generating a local oscillator signal for mixing with a received signal to produce an IF signal at a certain IF frequency, said frequency synthesizer means being digitally controlled and being responsive to an applied frequency code to develop a local oscillator frequency for reception of a signal at a frequency corresponding to the applied frequency code, a detector circuit including means for developing on a signal present line a signal indicating the receipt of a signal by the receiver, processor means including read only memory means for storing service group identification data which identifies a plurality of service bands each including a group of frequencies differing from one another by a certain incremental value with a limit frequency of the group being identified by a first data portion and with the number of frequencies in the group being identified by a second data portion, keyboard means for supplying control data for selection of said service bands, means connecting said processor means to said signal present line and to said keyboard means, said processor means including code-developing means responsive to control data from said keyboard means and to corresponding service group identification data from said read only memory means for developing a series of frequency codes corresponding to said limit frequency and frequencies differing therefrom and from each other by said certain incremental values with the number of frequency codes in said series being equal to the number of frequencies in said group, output means for sequential output of said series of codes to said synthesizer means, and means for inhibiting operation of said output means in response to a signal on said signal present line.