Linux - NT ppp using analogue line (null modem driver on nt)

Linux - NT ppp using analogue line (null modem driver on nt)

Post by Tony Da Silv » Thu, 11 Oct 2001 03:59:35



HI,

Hopefully somebody can help me. I've got a analogue leased line with a
Duxbury leased modem at a remote branch, it was connecting between 2 NT
machines over this analogue line using a NULL MODEM driver. I have to
migrate the branch to a linux machine and it has to connect to the NT
machine across this same analogue link using the duxbury modem.

I've been battling the entire day trying to get it going, but dont know how
to set up the connection as a null modem ?
with wvdial I'm connecting to /dev/ttyS0 and I keep getting responses that
"Modem is not responding"
The analogue modem however has connected to the other side as the CD light
is on - I just need to establish a ppp session between this linux machine
and the NT machine.

Please help before I pull all my hair out :)

--
Thanx guys !
Tony

 
 
 

Linux - NT ppp using analogue line (null modem driver on nt)

Post by David Efflan » Thu, 11 Oct 2001 13:03:24



Quote:

> Hopefully somebody can help me. I've got a analogue leased line with a
> Duxbury leased modem at a remote branch, it was connecting between 2 NT
> machines over this analogue line using a NULL MODEM driver. I have to
> migrate the branch to a linux machine and it has to connect to the NT
> machine across this same analogue link using the duxbury modem.

> I've been battling the entire day trying to get it going, but dont know how
> to set up the connection as a null modem ?
> with wvdial I'm connecting to /dev/ttyS0 and I keep getting responses that
> "Modem is not responding"
> The analogue modem however has connected to the other side as the CD light
> is on - I just need to establish a ppp session between this linux machine
> and the NT machine.

Read the PPP-HOWTO and use pppd directly (without wvdial and likely no
chat script, since you are NOT dialing).  Depending upon what
authentication is used, you may need to set up chap-secrets.

Otherwise you could set up an AutoPPP connection in /etc/inittab using
mgetty something like:

S0:12345:respawn:/usr/sbin/mgetty whatever_options

--
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Linux - NT ppp using analogue line (null modem driver on nt)

Post by Clifford Kit » Fri, 12 Oct 2001 00:52:09



Quote:> Hopefully somebody can help me. I've got a analogue leased line with a
> Duxbury leased modem at a remote branch, it was connecting between 2 NT
> machines over this analogue line using a NULL MODEM driver. I have to

Hmm..  A modem on one end and _none_ on the other seems to me to
mean that you have a nullmodem adapter on the local end.  That must
be the case unless the NT has software that actually uses a direct
serial connection by sending DCE crossover signals at the physical
layer to emulate a nullmodem.

Quote:> migrate the branch to a linux machine and it has to connect to the NT
> machine across this same analogue link using the duxbury modem.

If the NT actually does this then you will need a nullmodem
adapter-connector between the line and the serial port for Linux.

Quote:> I've been battling the entire day trying to get it going, but dont
> know how to set up the connection as a null modem ?  with wvdial
> I'm connecting to /dev/ttyS0 and I keep getting responses that
> "Modem is not responding"

Wvdial expects a modem or a nullmodem connection.  Moreover, wvdial is
probably not what you want to use.

Quote:> The analogue modem however has connected to the other side as the CD light
> is on - I just need to establish a ppp session between this linux machine
> and the NT machine.
> Please help before I pull all my hair out :)

Well, we don't want that. ;)

I'd suggest abandoning wvdial and using a simple script that invokes
pppd in a way that is similar to one of these:

/usr/sbin/pppd /dev/ttyS1 debug crtscts modem 115200
  or this
/usr/sbin/pppd /dev/ttyS1 debug nocrtscts xonxoff local 115200

Which one you need depends on whether hardware or software flow-control
is used.  Since this connection is via a leased line without a modem
on one side I would *guess* that you need the second one.  The debug
option can be removed once the connection is known to work.

Since this is an NT you may (or may not) also need a connect script
added to these lines such as

connect 'chat -v "" CLIENT CLIENTSERVER \\c'
  or
connect 'chat -v "" CLIENTSERVER CLIENT \\c'

(I've never done this with an NT and don't remember the CLIENT and
CLIENTSERVER order)  The chat -v option can be removed once the
connection is known to work.

--

/* ... packets usually cross many administrative boundaries on their way
   from a source to a destination and often the only point of agreement
   between those separate administrations is that all problems are someone
   else's fault.   --Van Jacobson, abstract of April 97 MSRI talk */

 
 
 

1. Linux - NT ppp using analogue line (null modem driver on nt)

HI,

Hopefully somebody can help me. I've got a analogue leased line with a
Duxbury leased modem at a remote branch, it was connecting between 2 NT
machines over this analogue line using a NULL MODEM driver. I have to
migrate the branch to a linux machine and it has to connect to the NT
machine across this same analogue link using the duxbury modem.

I've been battling the entire day trying to get it going, but dont know how
to set up the connection as a null modem ?
with wvdial I'm connecting to /dev/ttyS0 and I keep getting responses that
"Modem is not responding"
The analogue modem however has connected to the other side as the CD light
is on - I just need to establish a ppp session between this linux machine
and the NT machine.

Please help before I pull all my hair out :)

--
Thanx guys !
Tony

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