Abstract: There is disclosed on external programmer for use with heart pacers of two different types. Depending on the reed orientations in the two types of pacers, the magnetic flux generated by the programmed has to be in one of two orthogonal directions through the pacers. A pair of parallel coils is provided. A switching circuit switches the current direction through one of the coils so that the two coil fluxes aid or oppose each other, thus giving rise to orthogonal fluxes through pacers to be adjusted. A pacer of either type can thus be adjusted without the physician having any concern for the reed/programmer orientations.