IBM Expansion
I'm sorry I sent my stash of memory adapters up to Fred Spencer...

286 Memory Expansion Adapter

ZM28-31, 39-41 30 pin SIMMs 

16 bit adapter

2-14MB Memory Expansion Adapter
J1-J4 72 pin SIMM socket U50 L1A4452

32-bit adapter
 
 

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with Lotus (1)/Intel (2)/Microsoft (3) Expanded Memory Specification (LIM EMS) Version 4.0 support for all PS/2 Models 50, 50Z, 55 SX, 60 and 65 SX.
       The Personal System/2 1-8MB 286 Memory Expansion Option is functionally equivalent to IBM's existing 2-8MB 80286 Memory Expansion Option (#8286, 6450609), but with 1MB of standard 85ns memory.  It is expandable in increments of 1MB or 2MB up to a maximum of 8MB by using existing Single In-Line Memory Modules (SIMMs), the 1MB Memory Module Kit-85ns (#5212, 6450603) or the 2MB Memory Module Kit-85n (#5213, 6450604).
       The Personal System/2 1-8MB 286 Memory Expansion Option can be used with OS/2 (R) Standard Edition Versions 1.2 and 1.3, or OS/2 Extended Edition Versions 1.2 and 1.3 as extended memory, or it can be used as expanded memory.  An expanded memory device driver
compatible with LIM EMS Version 4.0 is included.

4-14MB Memory Expansion Adapter FRU P/N 87F9916
2-14mem.exe These files are for the 2MB and 4MB 80386 Memory Expansion Adapter
2-14mem.txt
@FDDE.ADF - IBM Enh. 80386 Memory Exp. Adapter w/ROM 
CFDDE.ADF - Init file for @FDDE.ADF 
J1-J4 72 pin SIMM socket U50 L1A4452

Supports 1MB, 2MB, and 4MB 80nS or 85nS IBM memory.

Mandatory Replacement ENHANCED Enhanced 80386 Memory Expansion ECA 042

How to Seperate the FDDE, FDDF (old) and FDDF (new) Adapters
  All three share the same basic outline. The later IBM Enh. 80386 Memory Exp. Adapter (FDDF new) has a WHITE  (not off-black) single SIMM socket on the upper right. The FDDF card supports enabling or disabling Matched Memory.
   The IBM Enh. 80386 Memory Exp. Adapter (FDDF old) totally lacks the resistor networks below the SIMM sockets. It only has two epoxy coated capacitors on the left edge (not three).

  Which makes me wonder which came first.
My Pocket Reference sez

Option#  FRU #    Feature Code      Description
87F9856  87F0075  9856              2-14MB Mem Adapter (32 bit, 80nS only)
87F9860  87F0075  2190              4-14MB Mem Adapter (32 bit, 80nS only)

IBM Enhanced 80386 Memory Exp. Adapter 
@FDDF.ADF - IBM Enh. 80386 Memory Exp. Adapter 
CFDDF.ADF - Init file for @FDDF.ADF - required ! 
IFDDF.ADF - Init file for @FDDF.ADF - required ! 
_FDDF.ADF - IBM Enh. 80386 Memory Exp. Adapter alt file / more settings
 
 

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