Saw the post saying that the 33.6 was the best choice for the old PS/1, and
that triggered this thought:

You may be able to INSTALL a 56k, but RUNNING at anything above, say, 28.8
really causes problems with data "traffic jams" at the processor.  I
personally had to run my 33.6 at 19.4 in order for things to run smoothly.

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