Software Publishers, Inc.
50 pin to 34 pin adapter for 8” floppy drives
50 pin card edge connector to 34 pin card edge
Adapter copyright 1982

all odd numbered pins are connected together on each connector and 
between the connectors to create a common ground

50 pin #     34 pin #     50 pin Shugart
                          Pin Definition

   2          n.c.         Low Current
   4          n.c.          
   6          n.c.
   8          n.c.
  10          n.c.         Two Sided
  12          n.c.         Disk Change

  14           32          Side Select

  16          n.c.         In Use

  18           16          Head Load
  20            8          Index

  22          n.c.         Ready
  24          n.c.

  26           10          Device Select 1
  28           12          Device Select 2
  30           14          Device Select 3
  32            6          Device Select 4
  34           18          Direction
  36           20          Step
  38           22          Write Data
  40           24          Write Gate
  42           26          Track 00
  44           28          Write Protect
  46           30          Read Data

  48          n.c.
  50          n.c.


The adapter actually had card edge connections on both edges of the adapter.
The 50 pin side was also connected through the card edge connector.