I believe that means that there is no RS-232 connection between the K3S and P3. Check the K3S manual for the correct hookup. Alan N1AL On 10/8/2020 11:37 AM, Thaire Bryant wrote: > I have just noticed that after replacing my K3 with a K3S my P3 no longer > shows the center frequency of VFO A (7.234, 14.234, etc,).