[comp.dcom.modems] PP MNP modems and parity

david@wubios.wustl.edu (David J. Camp) (09/28/89)

Hi,  This is a followup on my recent posting about PP MNP modems.  I
have determined that they are reliable in block mode, but not in stream
mode with compression.  However they were still running very slow.
Finally I tried changing the default parity setting on the answering
modem to even, and it started working properly.  I suppose this has
something to do with the fact that Unix generates even parity, and it
was expecting no parity.  I have not retried it in stream mode since
then.  The problem is, at least one of our applications (Sun-Sas)
requires no parity, and we would generally like to use that mode for
faster file transfer and connections to VMS which also require no
parity.  Does anyone know why the MNP protocol slows way down when the
modem parity does not match the transmitted characters?  It seems like
no parity should do no translation on an 8-bit datum.

Any help would be appreciated.  Please reply directly to me.  Thank you,
-David-

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