12-20-93
                     USE of &Q6, &Q5, &Q0, &Q8 and &Q9

                                 Don Hinds
    (this applies to Zoom V-series modems, not RPI based 'Axx' modems)

     The  default  setting for Zoom V-series modems is  &Q5  which  enables
speed buffering, and enables protocol negotiation. When  you want  protocol
turned  OFF, use the &Q6 command which leaves the speed  buffering.  Either
typed directly   AT&Q6, or in the Dial Prefix AT&Q6DT. To turn it back  ON,
AT&Q5  or  AT&Q5DT  will do it. Sometime  &Q0 will help when  doing  slower
speeds   like  1200   or   300bps  and/or if you  want  to  have  a  direct
(unbuffered)  connect with  NO MNP4 or v42 error correction. If you do this
I  recommend   you  use the S37 register to set speed with  N0  command  to
specify modem speed.

     The best place to do this is in the dial prefix, or directly typed  in
terminal  mode.  The INIT string is not a good place, unless you  want  ALL
calls set that way.

     If  you know the connection will be MNP and not v42bis, then  you  may
want  to  turn OFF compression (MNP5) if you are transferring  files.  MNP5
tries  to compress ALL files, slowing down the transfer  of  pre-compressed
files slightly. (V42bis will pass-through compressed files so does not have
to  be disabled when transferring compressed files.) The &Q8  command  will
set   the   modem   to   negotiate MNP  (but  not  V42xx).   S46=136   sets
compression   OFF. AT&Q8S46=136  or  AT&Q8S46=136DT for MNP4 only. The  use
of  &Q5S46=138  will restore  full  negotiation.  If you want  MNP4/5  then
leave  out  the  S46= command. Also, using AT&Q9(DT) will act as if S46=128
and  &Q5. So you could leave  S46=136  and  use  &Q9  in  place of &Q5   to
get  just  EC  and  no compression.

     The  \N0 should not be used, because it also sets register 48 to  128.
The  \N3  does not restore S48 to 7, so an additional command  to  to  that
would  be needed to restore S48 to default.

    Normally  the  following  shouldn't  bee  needed,  as  they  never  get
nogotiated when you use &Q6 or &Q0.  %C0 turns off Compression (v42bis) but
leaves error checking (v42). %C1 turns on Compression. S48=128 disables v42
(and thus 42bis, S48=7 restores it.

                                   Don Hinds - Zoom Tech
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