What is the code used by VCR+?

Information on decoding the 1 to 6 digit code has been published in:
K. Shirriff, C. Welch, A. Kinsman, "Decoding a VCR Controller Code,"
  Cryptologia, 16(3), July 1992, pp 227-234.

A program to do the decoding (not written by the above authors)
is available by anonymous ftp to wuarchive.wustl.edu in
/usenet/alt.sources/articles/7000-7999/7020.Z