SUMMARY: modem dialin help (Zoom 14.4)

From: J. Matt Landrum (
Date: Thu Aug 27 1992 - 05:04:04 CDT

My outside mail has been acting up so I apologize for the delay
in the summary or if any mail directed to me bounced.

I had a problem dialing in to my Zoom modem. I removed and remade the
/dev/ttyd0 file, updated the gettytab file, and rebooted and have had
success. I still almost always have to lock the modem in at whatever
speed the modem calling in is capable of. I hope to be able to test
it with a newer model modem soon. I've included several debugging
hints I got from people which made tracing the problem much more
logical. One problem I was having (and still don't know why) is that
ttysoftcar was hanging. It was Sun Support who got me to remove the
ttya device, remove and remake /dev/ttyd0 (apparently you can use ttya
or ttyd0, I guess d0 is only of historical significance) turn off
getty in the ttytab file, reboot the machine, turn on the getty, and
check the value returned by ttysoftcar.

For those of you with Zoom V32.bis modems, here is the initialization
string I use when I need to allow dialin from an older 2400 baud modem.


changing s37 will lock the modem in at different speeds.

Many thanks to the following people for their time and effort:

Kevin Cosgrove
Phillip Akers
Benjamin Cline
Michael Sullivan
Hal Stern - NE Area Systems Engineer
Dave Shevett
Ed Romascan

================== original query, new comments enclosed in [ ] ==============

I've tried the comp.dcom.modems, comp.sys.sun.hardware, sun manuals,
the May 1991 stb, and Zoom technical support to no avail. If anyone
out there has a Zoom VFXV.32bis modem connected to a Sun, I'd like to
hear from you. When I told the first guy I reached at Zoom technical
support that I was trying to connect their modem to a Sun, he asked if
that was an IBM product! [I guess it's true, you get what you pay for]

Well, enough crying, here's the problem which I have been wrestling
with for some time now.

I have a Zoom Telephonics 14.4/14.4 VFXV.32bis modem connected to ttya
on a Sun 4/280 (4.1.1). I can dial out reasonably well (sometimes I
have to turn off protocol negotiating), but I'm having a hard time
dialing in to it. It connects, but I can never get a login prompt.
If I do a ps, I can see that the getty is still running which I assume
means that no login prompt has been issued (or at least no login
received). If I connect from both sides, I can type in one window
and see the characters appear in the other window which makes me
think getty is confused.

My sun devices look like the following

crw-rw-rw- 1 root 12, 128 Aug 14 14:51 /dev/cua0
crw--w--w- 1 root 12, 0 Aug 13 16:47 /dev/ttyd0

the entry in /etc/ttytab looks like

ttyd0 "/usr/etc/getty std.9600" dialup on modem

I have also tried

ttyd0 "/usr/etc/getty Auto-baud" dialup on modem

[I tried D2400 too, now I use D9600 and have modified /etc/gettytab
to look like the following:
# Fast dialup terminals, 9600/2400/1200/300 rotary (can start either way)


I have tried setting my modem up as a straight 9600 or 2400 baud
modem, but that doesn't work either. The modems I am trying to
connect from are a few years old which very well may be my problem.

Among the init strings I have tried are (if any of you happen to
have a Zoom out there):




currently my setup looks like

B1 E1 L2 M1 N1 P Q0 V1 W1 X4 Y0 &C1 &D3 &G0 &J0 &K0 &Q5 &R0 &S0 &T4 &X0 &Y0
S00:001 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:050 S08:002 S09:006
S10:014 S11:095 S12:050 S18:000 S25:005 S26:001 S36:003 S37:000 S38:020 S44:003
S46:138 S48:007 S49:008 S50:255

The modem is connected with a straight through 25-pin rs232 cable. It
tests ok.

I am using kermit with flow-control set to none. Once again,
sometimes I can connect, but that's it; no login prompt. I've tried
all combinations of parity and terminal bytesize (which I never
thought was the problem anyway). I get similar results using tip.

[It doesn't matter what you set flow-control to with this modem,
and my init string, and my cable]

The modem passes local diagnostics although it sometimes gets in a funny
state where all the L.E.D.s are blinking on and off.

[I still don't know what this means and the manual doesn't say anything.
 Since I have it working and fairly stable, it doesn't happen anymore]

Many thanks for any help. The last fax I got from Zoom technical
support had the following line: "We have no experience with any Sun
devices, so I cannot comment on those." If I do end up getting
some valuable help from them I will let you know in my summary.
Also, if anyone has any recommendations for the next modem I get,
let me know.

[The Zoom people are nice, they just don't know much about Suns]

====== end original query, start helpful replies, my comments in [] =======

From: Kevin Cosgrove 642-2676 <decwrl!qiclab!solomon!kevinc>


        Do a 'ps -aux' and look at the getty process. Here's mine right now:

        root 7865 0.0 2.5 56 288 ? S 22:33 0:00 - D2400 ttyd0 (getty)

        When the Sun thinks that a call has come in, the "?" changes to "d0".
        If that doesn't happen with your system, then check the Carrier Detect
        function and settings.

        Holler if you want more help.


[This is a good thing to do. My modem was answering and making a connection,
but the Sun never knew; the TT field stayed '?']



[boy, am I curious!]

I just checked my Zoom MX2400S modem on a Sun-3/160, and found the
unit works fine for both incoming and outgoing calls.

[Unfortunately, the SENDFAX software bundled with the modem only runs
on the MS-DOS micros.]

Your devices:
crw-rw-rw- 1 root 12, 128 Aug 14 14:51 /dev/cua0
crw--w--w- 1 root 12, 0 Aug 13 16:47 /dev/ttyd0

crw------- 1 uucp 12, 129 Aug 20 03:36 /dev/cua0
crw--w--w- 1 root 12, 1 Aug 20 03:09 /dev/ttyd0

[hmmmmm, I guess it doesn't matter what you name them as long as
the major and minor numbers are correct and they match the
port that you are connected to?]

Your /etc/ttytab entries:
ttyd0 "/usr/etc/getty std.9600" dialup on modem
ttyd0 "/usr/etc/getty Auto-baud" dialup on modem
ttyd0 "/usr/etc/getty D2400" vt100 on modem secure

where the "/etc/gettytab" entry switches speeds each time you press a
return or break key after establishing the connection:
# Fast dialup terminals, 2400/1200/300 rotary (can start either way)

Of course, you probably need to have some higher baudrates in the list.
I think that the Sun-3 might be limited to a maximum of 9600 baud, though.

For dialout, you just need to include an entry like
in your "/etc/remote" file, if you use "tip" to make your calls.

As far as the physical connection, I just use a flat ribbon cable with
clamp-on 25-pin connectors at each end!


From: decwrl!!freyr!pakers (Phillip Akers)

As for your modem problem... you might try setting your result codes to
the minimum setting... I had a problem like that on my WorldBlazer and
have also seen it on a TrailBlazer... of course these are Telebits but
you might be seeing the same problem... on my modem I set X(n), the
result code select to 0... I saw you had a X4 (if that is even the same
thing)... anyway good luck with it and stay in touch...



From: benji@mathsoft.COM (Benjamin Cline)

I just thought I'd mentioned that we have a Zoom v32 Turbo on our 4/110
(In fact I'm using it to type this message from home). In 9 months of trying
I have been unable get it to work to my satisfaction, and we are planning
on buying a Telebit to replace it.

If you are interested, I'd be happy to send you a copy of my modem settings.


[I've heard a lot of these types of comments lately]

From: decwrl!uunet.UU.NET!trdlnk!mike (Michael Sullivan)

I don't know anything about the Zoom modem, so I can't comment on all
your current settings, but here are a few tips:

"modem" is not a legal keyword in the /etc/ttytab file!
It may be confusing init or the ttysoftcar command.

[it may have been confusing it before I finally rebooted. the man pages
say that it just check the field for the "local"

here are some good tips for you guys and gals out there mucking with
modems, also see the May 1991 Sun Software Technical Bulletin

General modem configuration tips:
 disable echo (E0). Otherwise if the getty ever tries to output a login prompt
        while the modem is in command mode, the modem will echo it back to
        getty, which will think it is a login name, prompt for a password,
        not like what it gets back, and loop forever like this.
 disable status messages (Q1). Otherwise it will feed the "CONNECT" message
        to the getty, which will think it is a login name.
 assert CD (Carrier Detect) when and only when it is connected.
 assert DSR at all times.
 assert CTS under normal (idle) conditions.
 if you can, lock the modem's DTE rate at 19200 or 38400; getty's autobaud
 feature is unreliable at worst, and annoying at best.

[here again, is the thing that pointed me to the problem]

If things are configured properly, if the modem is not connected "ps
-aux" should show the getty with a "?" in the TT column, indicating
that since CD isn't asserted, it can't open the port. Once the modem
has answered, ps should show "d0" in the TT column, indicating that the
modem was able to open the port.

Use stty to monitor the settings of the /dev/ttyd0 port once getty has
been able to open it. Beware of the two versions of stty (/usr/bin and
/usr/5bin) -- they must be used differently. I prefer using:
        /usr/5bin/stty -a </dev/ttyd0

If you are still having problems, run trace on the getty process and
see what it is doing.


From: stern@sunne.East.Sun.COM (Hal Stern - NE Area Systems Engineer)

instead of "modem" put "remote" in your /etc/ttytab file,
and make sure that the system is really not starting the
getty until the modem picks up. also make sure the modem
is driving DCD the right way, and that your cable passes
pin 8 straight thru.

what's the gettytab entry for auto-baud?

[a lot of the Sun docs say that the Auto-baud entry can be unreliable]

getty issues the login: prompt, and once you type at it,
it forks off login to get a password. sounds like your
remote modem is having problems negotiating speed and
protocol with the local modem. what happens if you
try it at fixed, 2400 buad, no autobaud?



From: decwrl!!sparc!shevett (Dave Shevett)

Not to nitpick, but might be a valid point:

> If I do a ps, I can see that the getty is still running which I assume
> means that no login prompt has been issued (or at least no login
> received).

Getty does not spin off 'login' until after someone has entered a
login name. 'getty' is the program that actually spits out
the word 'login: ' on the terminal.

just a thought...


From: decwrl!suntan.West.Sun.COM!mrt!ed (Ed Romascan)

Matt -

I don't have a Zoom modem, but the following looks suspicious:

        Check the meaning of the &Q setting, on my modems it turns
        on synchronous operation.

        On some modems, the &f command takes some time so I have to
        wait for the OK before I send out the rest of the init

        Check the lights on the modem when the connect occurs to make
        sure that CD come on. If CD does not come on, the two modems
        are not negotiating the connection properly. You can try a
        lower speed and no protocol, ie 2400bps, and work through the

        If the CD light comes on and the LOGIN never occurs the CD is
        not getting to the driver. The driver sleeps in the open until
        CD goes high, then completes the open and issues the LOGIN.

       [the CD lights on both modems were coming on]

I hope this helps, please summarize your findings.

[it did and I will]

Good Luck

Ed Romascan


Matt Landrum |
Cypress Southeast Design Center | office: (601) 324-4609, FAX - 4614
1 Research Blvd, Suite 200 | "There's a fine line between
Starkville, MS 39759 | stupid and clever" -- Spinal Tap

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