SUMMARY: Configuring Modem on SunOS 4.1.3 & tip

From: Henrik Schmiediche (
Date: Tue Feb 28 1995 - 00:22:21 CST

my question concerned setting up a USR Sportster 28.8k V.34 modem to a
Sparc IPX. I was able to dial in, but I was not able to use 'tip' to
dial out and/or to configure the modem. I was using /dev/ttyb as my
serial I/O device. It turns out that this will not do and one must
different dial in and dial out devices. Several people also asked me
about setting up the modem in general, so here is the list of steps I
used to get my modem to work on an IPX running SunOS 4.1.3. My main
purpose was to dial in to the system. I probably made mistakes below
or left things out. If people send me corrections I will post a
corrected version in a few days.

   0) First do an archie search for "". This is a 20
      page guide to setting up modems on a Sun's. Highly recommended
      reading for anyone wanting to set up modems on a Sun. If you
      are using Solaris get "Celeste's Tutorial on Solaris 2.x Modems
      & Terminals" (~ftp/pub/sun-faq/FAQs on Even
      if you do not use Solaris this guide might be useful.

   1) Hook up the modem using a straight thru serial cable. On the
      Sportster turn dip switches 3 (enable result codes display),
      8 (enable AT command set recognition) and 5 (enables auto answer)
      to on. Some users indicated that tip does not understand extended
      result codes and they should be turned off. I have not yet done
      this, but then all I use tip for is to configure the modem. See
      the comments by US Robotics technical support later on.
   2) Set the eeprom:

        eeprom ttyb-rts-dtr-off=false
        eeprom ttyb-ignore-cd=true
        eeprom ttyb-mode=38400,8,n,1,h

      and reboot system so that they take effect. Some people said this
      was not strictly necessary. Please note that the speed 38400 is not
      supported or recommended by Sun. It seems 19200 is the best Sun
      recommends. Sun's serial I/O is not buffered and 38.4K may result
      in dropped characters. On a Sparc 20 I've had no problems with
      38.4k, on a Sparc IPX the verdict is still out. File transfers
      seem to occasionally fail.

   3) Here is where I messed up originally. Create the dial in device:

          mv /dev/ttyb /dev/ttyd1 (or /dev/ttya to /dev/ttyd0)

      Why this is necessary I do not know. Anyone? Then create the
      dial out device:
         cd /dev
         mknod cua0 c 12 128 (for ttya)
         mknod cua1 c 12 129 (for ttyb)

   4) edit /etc/remote and add or change one or both these lines:


      to test if it works:

         tip cua1

      should connect you to the modem on serial port b. Configure the
      modem as desired (see US Robotics comments later on).

   5) edit /etc/gettytab and add/modify this line (add the 'p8'):

   6) edit /etc/ttytab and modify the line that starts with "ttyb" to:

        ttyd1 "/usr/etc/getty std.38400" vt100 on remote

      then do a "kill -1 1" to re-init the init process. Do a
          % ps -ax | grep 38400
          17813 ? IW 0:00 - std.38400 ttyd1 (getty)

      to see that its running.

And thats it folks! You should be able to dial into the modem... I think...

Thanks to all who responded!!!

    - Henrik

Here is some comments by US Robotics on setting up & configuring
modems on a Sun:

From: "Customer Support" <>
Subject: Re: Sportster Setup
In order to configure the software properly with your Sportster, issue
the following command in terminal mode: "AT&F&B1&H1&R2&A3&K3X4S11=38".
After getting the "OK" response, issue an "AT&W" to write it into
NVRAM. All of your initialization strings in your communications
packages should read "ATZ", along with the carriage return symbol
(different for each software package. If you do not want to write the
string to your NVRAM, use the above init string in your software
configuration. Do not use the &W.
"&F" - Reset to factory defaults
"&B1" - Lock DTE (computer to modem) speed at the speed of last AT
command. This is necessary for high speed modems in order to use data
compression. It is also necessary if your connection rate does not
match your DTE speed (i.e. port speed at 19200 in software, and you
make a 14,400 connection. If this happens with &B0, you'll get
"&H1" - Hardware send flow control. Uses the CTS signal to regulate.
"&R2" - Hardware receive flow control. Uses the RTS signal to regulate.
"&A3" - Extended result codes display. Enables the modulation, error
correction and data compression types the modem has connected with.
"&K3" - Selective data compression. If you cannot establish a V.42bis
connection, it will not attempt an MNP5 connection. Useful when
transferring already compressed files (ZIP, ARJ, LZH, etc.). V.42bis
is fast enough to not slow down the transfer if the file is already
compressed. MNP5 will drastically slow the transmission.
"X4" - Extended result code set. Enables the modem to report the line
conditions for "BUSY", "NO DIAL TONE", and "NO ANSWER".
"S11=38" - Reduces the time delay in between dialing tones.
"&W" - Write to the modem's non-volatile RAM. Each time you reset the
modem with "ATZ" or recycle the power, it will come up with the
parameters stored in NVRAM.
In your software package, choose a port speed of 19200 (115200 for the
28.8), set XON/XOFF software flow control to OFF, CTS/RTS hardware
flow control to ON, DSR/DTR flow control OFF, Autobaud detect OFF.

US Robotics On-Line Support

From: "Customer Support" <>
Subject: Re: Sparc Setup Sportster
To set up your Sportster modem on a SUN SPARCstation 2, there are
several steps that you must take. First, you must set up your modem
before you attach it to the SUN machine. Leave DIP switches 3, 5, and
8 in the DOWN (ON) position. With a PC, program the modem the
following method: Issue the command "AT&F&B1&H1&R2&K3X4S13=1&W". This
will write the string into the modem's NVRAM settings, so whenever you
power up the modem, it will come up with those defaults. Put DIP
switches 4, and 8 in the DOWN (ON) position. You are now ready to put
the modem on the SUN SPARCstation. After you have connected the modem
to the SUN SPARCstation, make note of the "TR" light on the modem. If
the light does not come on, then the system does not supply the DTR
signal, and you will have to force DTR high by DIP switch 1. Your
"TR" light should then light up. The modem is ready for use on the
SUN SPARCstation. You should set up the SUN for a port speed of 19200
and hardware flow control (CTS/RTS). If you are still experiencing
the same problem (with garbage), then drop the port speed to 9600. It
should then work properly.
Thank You.
U.S. Robotics On-Line Support

Henrik Schmiediche, Dept. of Statistics, Texas A&M, College Station, TX 77843
E-mail:  |  Tel: (409) 862-1764   |  Fax: (409) 845-3144
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