[Kenwood] query re optional board in 940S

[Fern]

    I recently purchased a very nice high serial number TS-940s 10M series 
and it came with an aftermarket pc board installed in the location normally 
used by the digital voice recorder. It has two 16 pin IC's on it marked 
CD4027BCN and CD4040BCN. It has a two wire output that goes to the top board 
to do with the bank select.  Does anyone know who made this? Looking for any 
documentation so that I can make use of it.
      73 from Fern