[En-Nut-Discussion] Two Nut/OS boxes do not communicate witheachother

Ernst Stippl ernst at stippl.org
Wed Dec 13 08:39:31 CET 2006

Hi Willem!

I assume that you are using the serial I/F to connect from the Ethernut to
the  GPRS modem (phone), right?

If that is the case, it would require a little HW fiddling to be able to use
Ethereal to show what is going on within the PPP protocol:

The 9-pin serial I/F has a TX (transmit) and RX (receive) line (pin 3 and 2
of the DB9 connector). You need to get into the DB9 connector and tap into
pin 2 and pin 3.

If you connect these two pins to SEPARATE RX pins in two DIFFERENT serial
I/F on a PC, you could use a program like "SerialAnalyser" to listen and
capture the data (going in and out of the Ethernut) and produce a PCAP file
which in turn can be analyzed and displayed by Ethereal...

Not a very easy way, but  working.

One more thought: Do you connect from the PC (when using it instead of one
Ehernut) to the Ethernut board or vice versa? Have you added routing
information using the "NutIpRouteAdd" function into your Ethernut app?


-----Ursprüngliche Nachricht-----
Von: en-nut-discussion-bounces at egnite.de
[mailto:en-nut-discussion-bounces at egnite.de] Im Auftrag von Willem Myburgh
Gesendet: Mittwoch, 13. Dezember 2006 07:18
An: Ethernut User Chat (English)
Betreff: Re: [En-Nut-Discussion] Two Nut/OS boxes do not communicate

Hi There

We have a private APN, which allocates fixed IP addresses to our mobile


On 12/13/06, Krzysztof Drewicz <hunter at mimuw.edu.pl> wrote:
> Willem Myburgh napisał(a):
> > The PC is also connected to the GPRS network.
> >
> >
> >> We use PPP. Each system connects to a GPRS network.
> With 95% of certain your GSM operator blocks direct p2p connections in 
> First try to setup a serwer (anywhere in the internet) and use some 
> simple tcp application. You could use some netcat/redir combinantion 
> or write some app in perl.
> It will open a pair of sockets, read on one port and forward to the 
> another socket if the second one is connected.
> In Poland most GSM providers count up to 2 Euro extra charge / month 
> for one public IP on the GPRS, it's not firewalled by any means i.e. 
> you are on your own and your ethernut box is connected to the Internet 
> with public ip, you should consider this in your setup.
> Also, you could use some GSM based VPN, you will have your own virtual 
> network like (in most cases it is small) but it's 
> firewalled from the Internet, you have access to the net, and p2p 
> communication is not restricted, also in Poland it costs sth like 
> 200-300 Euro / month for 10 sim cards.
> Best Regards.
> _______________________________________________
> http://lists.egnite.de/mailman/listinfo/en-nut-discussion

Willem Myburgh
South Africa
Mobile: +27834150416

No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.409 / Virus Database: 268.15.15/581 - Release Date: 09.12.2006

No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.409 / Virus Database: 268.15.16/582 - Release Date: 11.12.2006

More information about the En-Nut-Discussion mailing list