https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/4/897/ENUS188-024/index.html

The Personal System/2 Multi-Protocol Adapter/A provides a
full-duplex or half-duplex multi-protocol serial data transmission
channel. It supports asynchronous, bisynchronous, HDLC, or SDLC
protocols. It will support modems or direct attachment. The option
is programmable at speeds of up to 19,200 bps and supports automatic
protocol switching via software at setup.

On Tuesday, November 9, 2021 at 8:57:51 AM UTC-7, Louis Ohland wrote:
> https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/4/897/ENUS188-024/index.html
>
> The Personal System/2 Multi-Protocol Adapter/A provides a
> full-duplex or half-duplex multi-protocol serial data transmission
> channel. It supports asynchronous, bisynchronous, HDLC, or SDLC
> protocols. It will support modems or direct attachment. The option
> is programmable at speeds of up to 19,200 bps and supports automatic
> protocol switching via software at setup.

https://www.ebay.com/itm/142188857700

He has a single, NIB adapter, marked as "without ZM1" - I thought there was a listing for multiple boards without 'ZM1' as well.

Huh, not coming up with MPCA with ZM1, but I'll look.

On 11/9/2021 10:36, IBMMuseum wrote:
> On Tuesday, November 9, 2021 at 8:57:51 AM UTC-7, Louis Ohland wrote:
>> https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/4/897/ENUS188-024/index.html
>>
>> The Personal System/2 Multi-Protocol Adapter/A provides a
>> full-duplex or half-duplex multi-protocol serial data transmission
>> channel. It supports asynchronous, bisynchronous, HDLC, or SDLC
>> protocols. It will support modems or direct attachment. The option
>> is programmable at speeds of up to 19,200 bps and supports automatic
>> protocol switching via software at setup.
>
> https://www.ebay.com/itm/142188857700
>
> He has a single, NIB adapter, marked as "without ZM1" - I thought there was a listing for multiple boards without 'ZM1' as well.
>

Well, spank me courageous... searching for ZM1...

MULTIPROTOCOL ADAPTER FRU P/N90X8995 (OPTION #6451003) REPLACES
FRU P/N72X8530 (OPTION #6450348). FRU P/N90X8995 IS SUPPORTED IN
THE FOLLOWING MACHINE TYPE/MODELS.

Note: There is a new level FRU ( P/N85F0004 ) now available that
has in turn replaced P/N90X8995.

8550-A00 8550-B00 8550-C00 8550-021 8550-031 8550-061
8550-900 8560-041 8560-071 8580-041 8580-071 8580-111
8580-311 8570-E61 8570-121 8570-A21 8573-061 8573-121
8555 - 031 8555-061 8565-061 8565-121 8590-XXX 8595-XXX

CAUTION:

OLD LEVEL MULTIPROTOCOL ADAPTER FRU P/N72X8530 (OPTION #6450348)
IS STILL SUPPORTED IN THE 8550-021, 8560-041, 8560-071, 8580-041
AND 8580-071.
OLD LEVEL CARDS MAY DISPLAY ERROR CODE 10062 OR INTERMITTENT
ERROR CODES 10029, 10030, AND 10031 IF INSTALLED IN ANY OF THE
REMAINING MACHINE TYPE/MODELS LISTED ABOVE THIS CAUTION.

THE NEW LEVEL CARD IS DOWNWARD COMPATIBLE (CAN BE USED ON ALL
MODELS) AND WILL BE SUBSTITUTED IF AN OLD LEVEL CARD IS ORDERED.

HOW TO IDENTIFY THE TWO ADAPTER CARDS:

1. RAW CARD ASSEMBLY P/N6278226 OR P/N72X6821 ARE USED ON
THE DOWN LEVEL ADAPTER. RAW CARD ASSEMBLY P/N90X8459 IS USED
ON THE NEW ADAPTER. (RAW CARD PART NUMBER IS LOCATED NEAR THE
CARD RETAINER).
2. NO COMPONENT IS INSTALLED AT LOCATION ZM1 ON THE DOWN LEVEL
ADAPTER (ZM1 IS LOCATED ON THE UPPER RIGHT HAND CORNER OF
THE ADAPTER). THERE IS A COMPONENT INSTALLED AT LOCATION ZM1 ON
THE NEW ADAPTER.

Well, turbo-spankulate me...

SYMPTOM:
01291300 errors and OS/2 Trap 0002 errors while running
applications which use the MPCA (Multiprotocol Adapter/A).

PROBLEM ISOLATION AIDS:
1. The system unit has a 66Mhz or faster processor.
2. A Multiprotocol Adapter/A is installed.
3. No diagnostics fail.

FIX:
On higher speed PS/2 systems (66MHZ and greater), a DMA timeout
error may occur due to timing factors associated with speed of
the system processor.

The fix for this problem is to replace the MPCA Adapter/A with
FRU P/N96F9156 which corrects the problem.
If the MPCA adapter currently installed is FRU P/N96F9156, this
tip does not apply and routine problem determination should
continue. Refer to RETAIN record # H017325 for additional
information and guidance.

When current inventories of FRU P/N85F0004 are exhausted, all
All orders for it will be automatically substituted to the new
FRU, P/N 96F9156.

Non Pentium processor Systems running at speeds at, or below,
33mhz have no operational problems with FRU P/N85F0004 and this
adapter should not be swapped to the new FRU part number unless:
1. The MPCA adapter installed is failing -and-
2. Current inventories of 85F0004 are exhausted.

For information on having FRU P/N85F0004 reworked to the current
level (FRU P/N96F9156) contact Charlie Hoffecker at T/L 795-4517
or (407) 595 - 4517.

On Tuesday, November 9, 2021 at 10:33:46 AM UTC-7, Louis Ohland wrote:
> Well, turbo-spankulate me...
>
> SYMPTOM:
> 01291300 errors and OS/2 Trap 0002 errors while running
> applications which use the MPCA (Multiprotocol Adapter/A).
>
> PROBLEM ISOLATION AIDS:
> 1. The system unit has a 66Mhz or faster processor.
> 2. A Multiprotocol Adapter/A is installed.
> 3. No diagnostics fail.
>
> FIX:
> On higher speed PS/2 systems (66MHZ and greater), a DMA timeout
> error may occur due to timing factors associated with speed of
> the system processor.
>
> The fix for this problem is to replace the MPCA Adapter/A with
> FRU P/N96F9156 which corrects the problem.
> If the MPCA adapter currently installed is FRU P/N96F9156, this
> tip does not apply and routine problem determination should
> continue. Refer to RETAIN record # H017325 for additional
> information and guidance.
>
> When current inventories of FRU P/N85F0004 are exhausted, all
> All orders for it will be automatically substituted to the new
> FRU, P/N 96F9156.
>
> Non Pentium processor Systems running at speeds at, or below,
> 33mhz have no operational problems with FRU P/N85F0004 and this
> adapter should not be swapped to the new FRU part number unless:
> 1. The MPCA adapter installed is failing -and-
> 2. Current inventories of 85F0004 are exhausted.
>
> For information on having FRU P/N85F0004 reworked to the current
> level (FRU P/N96F9156) contact Charlie Hoffecker at T/L 795-4517
> or (407) 595 - 4517.

Great data! - There was other information it was linked to the PS/2 model. Why does this material seem so familiar? I am remembering something like this being up in the past.

> For information on having FRU P/N85F0004 reworked to the
> current level (FRU P/N96F9156) contact Charlie Hoffecker...

BTW, he has a profile on LinkedIn too...

It might be the old and newer are downlevel?

MULTIPROTOCOL ADAPTER
FRU P/N90X8995 (OPTION #6451003) REPLACES FRU P/N72X8530 (OPTION #6450348).

FRU ( P/N85F0004 ) has replaced P/N90X8995.

So...
Old FRU P/N72X8530 (OPTION #6450348)
Newer FRU P/N90X8995 (OPTION #6451003)
Newest FRU ( P/N85F0004 )

OLD LEVEL MULTIPROTOCOL ADAPTER FRU P/N72X8530 (OPTION #6450348)
> STILL SUPPORTED IN 8550-021, 8560-041, 8560-071, 8580-041 AND 8580-071.

OLD LEVEL CARDS MAY DISPLAY ERROR CODE 10062 OR INTERMITTENT ERROR CODES
10029, 10030,
AND 10031 IF INSTALLED IN ANY OF THE REMAINING MACHINE TYPE/MODELS
LISTED ABOVE THIS CAUTION.

THE NEW LEVEL CARD IS DOWNWARD COMPATIBLE (CAN BE USED ON ALL MODELS)
AND WILL BE SUBSTITUTED IF AN OLD LEVEL CARD IS ORDERED.

HOW TO IDENTIFY THE TWO ADAPTER CARDS:
>
Old RAW CARD ASSEMBLY P/N6278226 OR P/N72X6821 ARE USED ON DOWN LEVEL
ADAPTER.

New / Newest
  RAW CARD ASSEMBLY P/N90X8459 IS USED ON THE NEW ADAPTER.

(RAW CARD PART NUMBER IS LOCATED NEAR THE CARD RETAINER).

Down level
Downlevel -
No ZM1

Newest - ZM1

(ZM1 IS LOCATED ON THE UPPER RIGHT HAND CORNER OF THE ADAPTER)

Downlevel
> Old FRU P/N72X8530 (OPTION #6450348)
> Newer FRU P/N90X8995 (OPTION #6451003)

New Level
FRU ( P/N85F0004 )
FRU P/N96F9156 replaces P/N85F0004, rework is possible...

https://fccid.io/ANO9SA6450348

The last version still uses the same FCCID as used by the earliest MPCA.

1987-03-31, but no further info.