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Unable to establish a PPP connection

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Hi everybody,

a few years ago I developed an embedded solution where my RCM3700 communicates on internet via the GPRS connection of a Cinterion MC55i terminal. The PPP connection is established through the TCP/IP Dynamic C libraries (9.62), RS232 interface, baud rate 115200, RTS CTS hard flow control. Everythink it works well.

Now I need to replace the modem with the newer BGS2T RS232 model but I've got some incompatibility issues. It seems to be something related to PPP handshaking that it fails.
At first I though it was some incompatibility with the new modem so I requested supporto to Gemalto support but with no success.

Then I tried to connect the modem to my Mac with a FTDI RS232 USB adapter and I discovered that it works. So I suspect some problems in the Dynamic C libraries.
Are there any updates for them? In the past I've already installed all patches availables.

I hope someone could suggest me how to resolve this issue. Any feedback is appreciated.
asked May 2, 2018 in Rabbit by cemit New to the Community (2 points)

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2 Answers

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There haven't been any recent PPP updates to Dynamic C 9. You can get the latest libraries from the GitHub repository: https://github.com/digidotcom/DCRabbit_9/commits/master

If you define PPP_VERBOSE in your program (or project options) does it report anything to give an indication of why PPP fails? Perhaps you need to add a setting via ifconfig().
answered May 2, 2018 by TomCollins Veteran of the Digi Community (1,458 points)
0 votes
Hi Tim,
I've enabled PPP_VERBOSE and others but I've got no useful informations (for me) to understand what it is the problem.

If you like, here you could see my verbose output: https://www.dropbox.com/s/5qnlpuk9t3ig8vm/log.txt?dl=0
answered May 3, 2018 by cemit New to the Community (2 points)
Sorry for my delay in responding.  Looking at the log, I see that the Rabbit sends credentials, receives a PAP Authenticate-Ack message, sends an IPCP LCP_CONFIG_REQ packet with what appear to be reasonable values (asking for IP, primary and secondary DNS, and not proposing values).

But the remote end responds with an LCP Terminate-Request.

Can you check the new modem's documentation to see if it lists any configuration requirements that may indicate settings for the Rabbit software?  Can you contact the modem's tech support people?
Hi Tim, I supposed there was something in the remote end side. I've already requested support to the Gemalto team but with no luck. Now I'm going to reply them with these new details.
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