5-12-94
    UNIX & XENIX & Terminals & Other NON-PC-non-dos-based applications
        (including VAX, pay telephones, remote controller or other)

     The  defaults for the modem are &C0  &D0, autoanswer OFF. For most  PC
applications  you  set  &C1   &D2.  Unix  and  Xenix  do  not  seem  to  be
standardized. Try combinations;  (AT&F sets defaults)

AT&F                AT&F&C1                  AT&F&D2
AT&F&C1&D2          (some rare cases may want &D3 - see manual)

     If  the  device cannot issue the init string to the modem  each  time,
finish  the line with &W and it will be saved to NV ram so the  modem  will
power-up with that configuration.

AT&F&C1&W    (example)

To set autoanswer to ON the command is S0=1     ATS0=1

     Commands  may  be combined on one line, AT&F at the start, &W  at  the
end.  The  modem will also 'wake up' at the same speed, parity,  bits,  and
stop bit that you were using at that time the AT.....&W command was issued.
So  always  use  the fastest (19,200 or 38,400) that  the  modem  and  port
support when you do the AT...&W.  CTS/RTS hardware flow control is  default
and best. The &K command sets flow control (see the manual).

>>>  On  some devices the &Sx and &Rx may need to be changed  from  default
(see your manual). DTR delay is controlled by S25. S38 can be increased  to
keep the modem from hanging up due to DTR dropping.<<<

     Another  default is E1 (command echo). Many systems prefer not to  get
command echos, so E0 should be included in  the string.

DUMB  MODE  >  Systems which do not want reponses to  commands  or  CONNECT
responses,  include Q1 in the string (default is Q0 to echo responses).  Q2
will  let the CONNECT reponses through, but inhibit command responses.  You
can  also trick the modem so it will not accept any commands. Change the  S
register  3 from ASCII 13 the carraige return character to something  else,
perhaps  the ASCII 61 for the '=' sign. Then any time YOU need to change  a
setting, you can type ATxxxx= and it will do the change.

     The %E2 will tel the modem to re-negotate the connection, (protocol  &
speed) while on-line. %E3 also enables fast hangup.

     If  you are having sending BREAK or BUFFER (getting  empty)  problems,
try \K0 through \K4 (see manual -  \K5 is default).

    In  working with one SCO Unix user these strings worked.

ANSWER  modem: AT&F&C1E0Q1S0=1 (&W)
calling modem: AT&FQ1S0=0      (&W)




     One Mini-computer user reports this works:

ANSWER  modem: AT&FE0&R1S0=1 (&W)   <-- note: these two had to change &R1
calling modem: AT&F&C1&R1    (&W)   <-- from default &R0

     The  &W also saves the 'current' speed, parity, bits and stop bit,  so
the modem will wake-up with those defaults.

     The SUN system with a Systech MTI board requires a special cable  (see
you manual "Adding hardware to your system"). Following that diagram should
be about 8 pages with information for setting the modem and the Unix.

     The  default for Zoom 'V' series modems is to use speed-buffering  (on
the  Turbo you need to set S36=7). This means you set your port  at  19,200
when  you setup the modem. When you use the modem, the modem takes care  of
modem-modem speed, buffering between the modem-computer.  To set BPS (often
incorrectly  called  Baud),  you merely set the  terminal  or  software  in
terminal  mode  at the BPS speed you want, and type AT to the  modem.  This
simple  procedure also sets Bits, Parity & stop bit. If you want the  modem
to 'wake up' at this BPS then type AT&W. The modem will stay at this BPS as
long  as  the  Terminal or software on the computer, does not  send  an  AT
command at any other speed.

     To  'lock'  port  modem speed, set the port at  the  speed  you  want.
(19,200  is often best). Set the modem ATS95=0 (default) and  the  software
may  then  either  be set to autodetect speed, or to  turn  autodetect  OFF
(best).  No matter what the carrier speed, when S95=0, the modem  will  say
CONNECT  19200 (or CONNECT 9600 if that was what you set), so the  software
will  not  issue  a command at the carrier speed, but only  at  the  pseudo
CONNECT speed, effectively LOCKING the port and modem.

     When using in Syncronous mode, along with these suggestions, also  see
your modem manual section on Syncronous for some  Zoom modems. Most do  not
have Syncronous mode.  When using &Q2 also include E0Q1 in the same line.

     The  pins  are  standard  RS-232. While PC  cables  are  always  25-25
straight  through  type  ( or 25-9pin), some  non-pc  may  need  Null-modem
cables,  where  pins 2/3 and 3/4 are swapped. They MUST  be  hardware  flow
control  cables, so an old cable from a 2400 modem may fail. On  2400  non-
V modems only some of the pins 2-8 and 20 are used.

                                   Don Hinds - Zoom Tech
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