SUMMARY : Problems with modem setup.

From: Lee Fook Heng (fhlee@csam.my)
Date: Thu May 19 1994 - 04:18:07 CDT


Hi Managers,

Thanks to all managers out there who responded to my questions.

I got quite a few responses for my questions about setting up modems
on Sun (IPX). Basically, the question was how to setup a modem on IPX,
a modem connected to an IPX works inconsistently (sometimes can connect,
other times cannot work), what are the default values for getty, etc.
The IPXs are running 4.1.3

Some has suggested me to refer to zyx_sun.ps in sgi.com:/sgi/fax on
how to setup a modem on Sun instead of referring to the Admin. manuals.
zyx_sun.ps is indeed very useful and provide a step-by-step intructions
on how to setup a modem and uucp on a Sun.

The problem regarding 'All ports are busy` when I tried to do 'tip cua0'
on a dial-in and dial-out port was solved by applying patch # 100513-04
jumbo tty.

Finally, I have solve most of the modem problems except for one.
Suppose I have 2 modems, named A and B. The problem is whenever I turned
off and on modem A,or pull the phone cable out (with or without turning
off the modem) from modem A, and when I tried to call in to modem A, what I
get is 'xxxxx~~~xxx'.

To solve this problem, I will have to go to the system connected to
modem A, do a 'tip cua0', 'at' or 'atz' and quit from tip. Then I tried calling
again to modem A, bingo, everyting works fine.

It seems to me like whenever I turn the modem off/on, the modem loses the
parity bit, databits, etc between the modem and DTE(IPX). So, I need to
let the modem knows what is the DTE's parity, databits, etc setting by
doing a 'tip'. I don't know if everybody experiences this problem.
According to my modem manual, the modem would automatically detects what
is the DTE's setting if there was 'communication' between the modem and
the DTE. So, if the modem was off/on and there is a dial-in after that
without first 'communicating' with the DTE, then, the modem would not know
what is the setting of the DTE. The modem manual does not show how lock
the modem's-to-DTE's databits, parity, etc. It says it is autodetect.
 
I don't know if this is the problem but will certainly be happy to hear
comments from you managers out there.

I have included the responses below.

Thanks to the following managers who replied :
   
    raoul@MIT.EDU
    rwolf@dretor.dciem.dnd.ca
    vina@hub.eng.wayne.edu
    glenn@uniq.com.au
    uu0101!goose.ca.pdc.com!dave@rambone.psi.net
    ca@informatik.uni-kiel.de
    justin@independent.co.uk
    dburwell@telecom.com
    brett@escape.com
    jerry@mafalda.univalle.edu.co

------------------------[ start of responses ]------------------------
>From raoul@MIT.EDU Sun May 1 22:57:43 1994
To: fhlee@csam.MY (Lee Fook Heng)
Subject: (none)
Content-Length: 417
X-Lines: 11
X-Status:

Forget the Sun Manuals on modems. Get the Zyxel paper, zyx_sun.ps.Z,
available from an ftp site near you.

Also, if you wish to use fax/modems, use flexfax. It's available from
sgi.com:/sgi/fax, and I use it very successfully on a Sparc II and an SGI
for sending/getting faxes, and for handling dial-ins. It auto-configures
for a wide variety of modems, very successfully.

                                Nico Garcia
                                raoul@athena.mit.edu
 
-----------------------------------------------------------------------
>From rwolf@dretor.dciem.dnd.ca Fri May 13 23:33:23 1994
To: fhlee@csam.MY
Subject: Re: Problem with modem setups ??
Content-Type: X-sun-attachment
X-Lines: 22
Content-Length: 797

If you are running SunOS 4.1.? you need patch # 100513-04 jumbo tty

good luck.
----------------------------------------------------------------------
>From vina@hub.eng.wayne.edu Sat May 14 08:08:40 1994
To: fhlee@csam.MY
Subject: Re: Problem with modem setups ??
Cc: sun-managers-relay@pandora.cs.wayne.edu, sun-managers@ra.mcs.anl.gov
Content-Length: 2644
X-Lines: 67

> From sun-managers-relay@pandora.cs.wayne.edu Fri May 13 10:45:34 1994
> Sender: sun-managers-relay@ra.mcs.anl.gov
> Reply-To: fhlee@csam.my (Lee Fook Heng)
> Followup-To: junk
> To: sun-managers@ra.mcs.anl.gov
> Subject: Problem with modem setups ??
> Content-Length: 1704
> X-Lines: 48
>
> Hi managers,
>
> I have a problem with using modems with suns and encounter some peoblems.
> The setups in the sun (editing /etc/ttytab, /dev/cuao) is ok. I am trying
> to coonect a radac and a hayes smartmodem.
>
> The problem is :
> 1) When I try to connect the modems, sometimes the modems don't seem
> to be able to 'handshake' (the modem answered the call, 'negotiate'
> for a while and just stops there). It happens when I try to answer
> with either the hayes or radac modem.
>
> Sometimes, when I try to connect, the modem is ok. I did not change
> anything on the modems and the modems are able to handshake, and I
> can get the 'login :' prompt.
>
> Does anybody know why us this. I did not notice any pattern why the
> modems were able to handshake and why it would not.
>
>
> 2) When I use the radac modem to connect a brand X modem, what I see is only
> xxxxxxx...x.x.x.x.x.x. characters instead of the 'login prompt'. As I notice
> the TD and RD light, it seems as though the connection is ok, but just
> that I don't get the correct characters. But when another brand X modem
> call the radac modem, its ok.
>
> It seems to me like it is the parity, data bits, etc setting is wrong. But
> I have set the other answering modem to 7 databits, 1 stop bits and even
> parity.
>
>
> Another question is, according to the Sys. Admin. book, suns has defaulted
> ttya/ttyb to have 7 databits, 1 stop bit, and no parity. But, when I do a
> 'eeprom' from the prompt, I see
>
> ttyb-mode=9600,8,n,1,-
> ttya-mode=9600,8,n,1,-
>
> does it mean that ttya/ttyb is 8 databits, 1 stop bit. How come its different
> from the admin book.
>
>
> Thanks for any responses. I will post a summary.
>
>
> -- fhlee@csam.my

( Any communication is not 100% error free). Asynconous communication has error for data transfers, modem comes with some number 1% -.001% error tolerence. The least number is batter.
 
On sun : 8 bit, even parity and 1 stop bits full duplex mode.

Some times you don't change anything and it works means your computer uses the
 default value or last set value which matches with our computers here.
The best way to make it work is always check or set baudrate, stop bits , parity , duplex mode and other parameters for asynconous communication.

-vina

------------------------------------------------------------------------
>From glenn@uniq.com.au Sat May 14 08:44:48 1994
To: fhlee@csam.MY
Subject: Re: Problem with modem setups ??
X-Sun-Charset: US-ASCII
Content-Length: 1115
X-Lines: 27

> Another question is, according to the Sys. Admin. book, suns has defaulted
> ttya/ttyb to have 7 databits, 1 stop bit, and no parity. But, when I do a
> 'eeprom' from the prompt, I see
>
> ttyb-mode=9600,8,n,1,-
> ttya-mode=9600,8,n,1,-
>
> does it mean that ttya/ttyb is 8 databits, 1 stop bit. How come its different
> from the admin book.

well, I can answer this one.

These settings affect what happens at the boot prompt. Once you boot
the kernel and the init process starts then it sets the parity, baud
rate, etc for the serial ports with it's defaults. Depending on which
version of SunOS the defualts are 7bits/even (=< 4.1.2) or 8 bits/none
( >= 4.1.3 and 5.x).

You can change the defaults in the /etc/gettytab file (SunOS 4.x).

regards,

--
Glenn Satchell                    glenn@uniq.com.au  | "This is a unix system.
Uniq Professional Services Pty Ltd  ACN 056 279 335  | I can do this easy."
PO Box 70, Paddington, NSW 2021, (Sydney) Australia  |
Phone 02 360 7434 Pager 016 287 000 Fax 02 331 2572  | - Lex, Jurassic Park
       "Sun Accredited System Consultants"           |

------------------------------------------------------------------------------ >From raoul@MIT.EDU Sat May 14 09:15:41 1994 To: fhlee@csam.MY (Lee Fook Heng) Subject: Problem with modem setups ?? Content-Length: 315 X-Lines: 8

Install jumbo tty patch, 100513-4. I have always found E-7-1 to work dialing into Sun's, with my modems. I also use the flexfax fax/modem software, which does most of the configuration itself, Check it out at sgi.com:/sgi/fax. This works extremely for my PPI fxmt modems.

Nico Garcia raoul@athena.mit.edu

------------------------------------------------------------------------------ >From uu0101!goose.ca.pdc.com!dave@rambone.psi.net Sat May 14 09:31:55 1994 To: fhlee@csam.MY Subject: Re: Problem with modem setups ?? X-Sun-Charset: US-ASCII Content-Length: 3315 X-Lines: 89

Hi,

Please see my comments below ...

David Haut Systems Engineer, PDC Services Inc. 510-449-3113 (VOICE) 510-449-3332 (FAX) ----/ ___ __ __ | /\/| / \ / \ / \ |/\/ | /____/ / / / /---- / _/___/ \___ Services, Inc

> From sun-managers-relay@ra.mcs.anl.gov Fri May 13 07:18:02 1994 > Sender: sun-managers-relay@ra.mcs.anl.gov > Reply-To: fhlee@csam.my (Lee Fook Heng) > Followup-To: junk > To: sun-managers@ra.mcs.anl.gov > Subject: Problem with modem setups ?? > Content-Length: 1704 > X-Lines: 48 > > Hi managers, > > I have a problem with using modems with suns and encounter some peoblems. > The setups in the sun (editing /etc/ttytab, /dev/cuao) is ok. I am trying > to coonect a radac and a hayes smartmodem. > > The problem is : > 1) When I try to connect the modems, sometimes the modems don't seem > to be able to 'handshake' (the modem answered the call, 'negotiate' > for a while and just stops there). It happens when I try to answer > with either the hayes or radac modem.

This could be a number of things. When you say that they don't handshake, what exactly do you mean?? Does the modem hang up? or do the modems appear to connect, but you get no login prompt ?? If it's the latter, make sure that you have getty set up properly on the Sun port. > > Sometimes, when I try to connect, the modem is ok. I did not change > anything on the modems and the modems are able to handshake, and I > can get the 'login :' prompt. > > Does anybody know why us this. I did not notice any pattern why the > modems were able to handshake and why it would not. > > > 2) When I use the radac modem to connect a brand X modem, what I see is only > xxxxxxx...x.x.x.x.x.x. characters instead of the 'login prompt'. As I notice > the TD and RD light, it seems as though the connection is ok, but just > that I don't get the correct characters. But when another brand X modem > call the radac modem, its ok.

This is a baud rate problem. Verify your modem settings. You want AUTOBAUD set for modem to modem communication ( called modulation speed in my modem documentation ). You want the DTE interface speed set to the same baud rate that you have the getty set up to on the port. > > It seems to me like it is the parity, data bits, etc setting is wrong. But > I have set the other answering modem to 7 databits, 1 stop bits and even > parity.

I don't think that this is a parity problem. If it was you would be seeing half of the characters, either the odd or even parity characters. > > > Another question is, according to the Sys. Admin. book, suns has defaulted > ttya/ttyb to have 7 databits, 1 stop bit, and no parity. But, when I do a > 'eeprom' from the prompt, I see > > ttyb-mode=9600,8,n,1,- > ttya-mode=9600,8,n,1,- These are the default settings when the port is closed. When you open the port by putting a getty on it for example, you should see these values change. You didn't specify what OS you were running, but if you are running 4.1.2 or below, the defauly parity settings for getty is 7,e,1. > > does it mean that ttya/ttyb is 8 databits, 1 stop bit. How come its different> from the admin book. > > > Thanks for any responses. I will post a summary. > > > -- fhlee@csam.my > >

--------------------------------------------------------------------------- >From ca@informatik.uni-kiel.de Mon May 16 15:54:05 1994 Subject: Re: Configuring modems with Suns To: fhlee@csam.MY (Lee Fook Heng) Content-Length: 406 X-Lines: 14

> Is this is correct, then I isn't it > right that I will always get 'xxxxxx' when I turn off and on the modem. How > can I solve this problem?

We initialize our modem with a tip connection every evening. To do this, we have installed the pty program (from Dan Bernstein (?)).

/usr/5bin/stty 9600 </dev/cua0 PTY=$HOME/bin/pty (sleep 10;/usr/5bin/echo 'ATZ\r') | $PTY -d tip cua0

Regards,

Claus Assmann

---------------------------------------------------------------------------- >From justin@independent.co.uk Mon May 16 20:18:31 1994 To: fhlee@csam.MY Subject: Re: Problem with modem setups ?? Content-Length: 95 X-Lines: 4

Which Sun???

There are known problems with Sparc IPC serial port and hardware handshaking...

---------------------------------------------------------------------------- >From telecom!telecom.com!dburwell@netcom.com Tue May 17 01:44:04 1994 X-Mailer: Cinetic Mail Manager V2.1 Reply-To: dburwell@telecom.com To: fhlee@csam.MY Subject: Re: Configuring modems with Suns Content-Length: 2857 X-Lines: 49

Welcome to the seamy underside to telecommuncation.

I may be able to help on one aspect, the modem to modem stuff.

There are 2 sides to a modem, the analog side (telephone) and digital (RS-232). When the calling computer talks to the calling modem, the digital side of the modem will, most likly, "auto-baud" to whatever the computer is sending, that includes bits, speed everything. When the sending modem reaches a modem at the far end, they will try to aggree on a speed that is as high as they can go. The bits, parity and stop bits will not change, only the speed. On ALL modems, the digital side will then change to the same speed as the analog side. What you have to do, is to program the modem so that the digital side is "locked" to either a fixed rate or stays that same rate as the last time the computer "talked" to it. The better way is a fixed rate. Check the manuals for your modems to see if the digital side can be locked, not all modems can. If yours can't be locked, then there is no way to guarante reliable connections every- time. It will depend on too many variables (phone noise, modem compatibility, last call speed, etc.).

EG: (Sparc or PC) You call out and have your terminal emulation program set for 56KBs 8n1. You reach a BBS (or something) and the modems aggree that the best they can support is 2400. The last thing you see on the screen is "Connect 2400" then the modem changes the digital side to 2400 expecting that the terminal emulation program (because it is looking for the word "Connect XXXX") will reprogram the serial port to 2400, then everything is set from end to end at 2400. This requires almost no flow control for file transfers and such. The problem is when the terminal emulation program doesn't support auto-baud, then the computer gets left behind when the modems change speed.

If the digital side of the modems are "locked" to 56KBs, then when they reach another modem and aggree on 2400, then the calling modem and computer will stay at 56KBs, but the analog side will be 2400. This will result in a lot of hand shaking on the calling computers side when you are sending something. That's a whole 'nother story. Sometime that works well, sometimes not.

Then again, it could be something completely different.

Good Luck Dave. -- ________________________________ =================== Don't become | | David Burwell - 408-428-7929| T E L E C O M Roadkill on the | FAX - 408-428-7895| -------------------"Data Super-Hype-Way" |Cust. Support BBS - 408-428-7908| S O L U T I O N S _ /| |Internet E-MAil Address: | =================== \'o.O' "AWK" | dburwell@telecom.telecom.com| a division of =(___)= _/ +--------------------------------+ Symmetricom Inc. U

---------------------------------------------------------------------------- >From brett@escape.com Tue May 17 02:39:49 1994 Subject: Re: Configuring modems with Suns To: fhlee@csam.MY Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 511 X-Lines: 14

I am not quite sure what the problem might be involving SunOs 4.1.3_u1, however I do know that resulting characters of 'xxxxxxxx' after an initial connect is almost always the result of a data baud rate mismatch. It occurs most often on slow baud rates such as 2400 and 9600 or lower. Further information on what type of modems are being used on the sending and receiving side might throw some more light on the issue.

Brett K. Lynch ------ brett@escape.com brett@iia.org system@psu.edu bkl104@cac.psu.edu

----------------------------------------------------------------------------- >From @CUNYVM.CUNY.EDU,@CUVMB.CC.COLUMBIA.EDU:jerry@mafalda.univalle.edu.co Tue May 17 01:04:12 1994 Subject: Re: Problem with modem setups ?? To: Lee Fook Heng <fhlee@csam.MY> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Length: 1650 X-Lines: 45

Greetings from Colombia - South America!

Lee,

I'll try to answer 1) because for 2) my modems are conected to a terminal server.

I've had two flavors of problem 1) before and it seems it was the local telephone company that was responsible.

Flavor a): Symptoms: People would try to connect and a modem would answer, but the calling modem never heard anything. A normal phone on the same line would work properly!

Explanation: The PBX connected to the modems had a problem (line polarization? You never get clear answers in Columbia...) and didn't recognize that the modems were "lifting the handset" (OH). The modems of course tried to synchronize with nobody...

Solution: Yell at the telephone company.

Flavor b): Symptoms: People would try to connect and a modem would answer, try to synchronize with the calling modem but they never would.

Explanation: The attenuation in the phone line was really high. Try this simply by calling with a phone to the modem and see if the carrier volume of the answering modem is low.

Solution: Yell at the phone company.

As you can see, the problem was somewhere else (that damned phone company). I just can't wait to see the summary.

Hope this helps. Good luck,

Jerry. +---------------------------------------------------------------------------+ | Jerry de Raad, Universidad del Valle - Colombia, Fax: ++57 23 39.85.17 | | Es mejor bueno por conocer que malo conocido. | +---------------------------------------------------------------------------+

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