SUMMARY: Resetting the Serial port on a SPARC 5

From: Mark `Hex' Hershberger (
Date: Thu Jan 23 1997 - 16:34:46 CST

Original Question:

> My boss and I both use the SPARCs on our desks to connect via modem.
> The problem is that, after disconnecting from a session, we have to
> manually reset the port like this

> > tip cuaa
> at
> OK
> ~.
> For whatever reason, this is needed to reset the port so that the next
> time we call in, we will be able to login. If we don't manually reset
> the port thusly, then we we call in, all we get is garbage.

> We're using Solaris 2.5

I got lots of responses, but the basic Idea was "Check what the modem does
with DTR." Before, my modem was set to

        &D3 -- DTR off, reset

Changing this to:

        &D2 -- DTR off, disconnect

did the job.

Thanks to the following for their responses:
        Bob Woodward <> (Celeste Stokely)
        "Liew.Chee.Wah" <>
        Anders Hammarquist <> (Kevin Sheehan {Consulting Poster Child})
        Satish Somanath <>
        Jacques Rall <>

Date: Wed, 15 Jan 1997 15:48:39 -0800
From: Bob Woodward <>

Check your modems configuration and how it responds to DTR. If you go to
hardware handshaking and reset on DTR drop, this should get you fixed up.
It's one of those things that is a real pain in the backside to try and
figure out from the modem's documentation.

Date: Wed, 15 Jan 1997 16:46:38 -0800
From: (Celeste Stokely)

If your port monitor and modem are properly programmed, you shouldn't
need to do this reset. Could also be the program you're using with
the port, like kermit.

Make SURE your modems are set to "reset to NVRAM when DTR toggles".

If they are, give me more details and I'll try to help. I'll need
modem type, modem register dump (please, oh please let it be a
"normal" modem--one I have docs for :-), a better description of
what happens if you DON'T reset it with tip, what port the modem
is on, and the output of "pmadm -l".

 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Celeste's Tutorials on Solaris 2.x/SunOS 4.1.3+ Modems & Terminals
        are available via the Web at
See our Web pages for lots of Unix Serial Port & Sysadm Resources!
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Date: Thu, 16 Jan 1997 13:58:40 +0800 (GMT+0800)
From: "Liew.Chee.Wah" <>

Dear Mark :

Do you quit the connection properly ? I mean type "+++" follow by "ath0"
if you get the OK prompt. This might be the problem why you get garbage
the next time you login via the modem.

Date: Thu, 16 Jan 1997 00:55:33 +0100 (MET)
From: Anders Hammarquist <>

I have a few ideas you could check out.

First, make sure the modem doesn't "auto-baud" (i.e. change it's
serial port speed depending on the speed of the connection with the
remote modem). You should also try sending a break if you get garbage
when you connect. If sending a few breaks gets you a prompt it's
definitely a speed problem.

Also check that ttymon is using the same speed to answer the port as
you use with tip to sync the modem. (I'm not sure if ttymon resets the
port after at tip session. It will be reset after a logout though.)
do pmadm -l and check the 6th "pmspecific" field. It should match an
entry in /etc/ttydefs, and that entry should have the same speed as
your port entry in /etc/remote (for tip).


 -- Of course I'm crazy, but that doesn't mean I'm wrong.
Anders Hammarquist                                  |
Not system administrator at DjungelData             | Fax: +46 31 772 3202
Chalmers University of Technology, G|teborg, Sweden | Tel: +46 31 772 3241

------------------------------------------ From: (Kevin Sheehan {Consulting Poster Child})

modem problem I guess - on mine there is an interaction between &D? and &Q? where some DTR transitions will disable auto-answer. You don't give the modem settings, but I suspect reading thru the stuff on auto-answer will be instructive.

------------------------------------------ Date: Wed, 15 Jan 1997 20:15:57 -0800 From: Satish Somanath <>

ttysoftcar -a

------------------------------------------ Date: Thu, 16 Jan 1997 12:37:12 -0800 From: Satish Somanath <>

> > ttysoftcar -a > > Intriguing.... but I can't find a ttysoftcar command anywhere. Care to > elaborate?

ttysoftcar was dropped in Solaris 2.5. It stayed in Solaris during the transition from Sunos to Solaris.

------------------------------------------ From: Jacques Rall <> Date: Mon, 20 Jan 1997 15:25:47 +0200

Look at basic modem programming: 36

"Hardware DTR, Normal DTR, or Reset When DTR Toggles. When the Sun drops DTR the modem should hang up the phone line and reset the modem to NonVolatile RAM settings. (On our it is AT&D2)

Hardware Carrier Detect or Normal Carrier Detect. The modem should only raise Carrier Detect (known as CD or DCD) when there is an active carrier signal on the phone connection. You'll setup the port monitor so that when CD goes active, the Sun will spawn a login.

When carrier drops, either when the other end of the connection terminated or if the phone connection is broken, the Sun will be notified and act appropriately. The CD signal is also used for coordinating dial-in and dial-out use on a single serial port." (on ours it is AT&C1)

_o ) Mark `Hex' Hershberger `\< New Orleans, LA ( (*)/(*) c[]

Abraham saw signs of God and believed. Now the only sign is that all the signs in the world make no difference. Is this God's ironic revenge? But I am on to him. -- Walker Percy, "The Moviegoer"

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