Gemalt EH6 Modem: Connection Failure Reason | Thales IoT Developer Community
July 29, 2017 - 10:22pm, 1193 views
Dear Staff:
I am using a Gemalto EH6S ****m in transparent PAD ****.
It isn't clear to me why the TCP connection establishment failure, described below
occurs. Any insight you have about the problem would be appreciated. Also, when
RF conditions are good, I am able to establish a TCP connection without problems.
The general problem is that after at least one connection failure, if you wait
about 2 minutes and attempt another connection, it fails with the following
diagnostic. All subsequent connection establishment attempts fail unless,
you turn the ****m off and then on again.
+CME ERROR: operation temporary not allowed.
The diagnostic after the first connection failure is something like this and
RF conditions are not too good.
^SIS: 2,0,94, "PDP: connection failed"
The sequence of AT commands issued to the ****m--via the serial port, in
the connection establishment attempts are as follows and only AT^SISO fails.
AT // Make sure ****m is alive
AT^SIP // Restore pre-programmed configuration.
AT+CSQ // Evaluate RF signal quality.
AT^SISO // Establish a TCP connection.
Best Regards,
Paul R.
Hello,
If there was no configuration change and the previous connections were working this "PDP: connection failed" information could suggest network problem. Have you checked the network registration status in such a case and network signal quality? Maybe you should also test with another operator with better coverage.
Could you paste some log where this problem can be seen and also what has been stored to the connection profile?
Is the previous connection always closed? Please try to check the connection profile and connection status with AT^SISI? and AT^SISO? commands.
Regards,
Bartłomiej
Hi Bartiomiej:
I am sure the cause of the first failure is bad RF conditions, and I
think I understand the cause of the subsequent failures where the diagnostic
is "+CME ERROR: operation temporary not allowed".
Even though the first connection fails and no true TCP network connection
is established, the modem internally allocates TCP connection resources.
My evidence is that after the first connection failure, you issue
a AT^SISC=2 AT command to the modem, then it returns to its
previous state and TCP connections can be retried with AT^SISO=2.
Best Regards,
Paul R.
Hello,
You are totally right that the connection opened with AT^SISO command must always be closed with AT^SISC command regardless of the fact if it was successful or not. It is not possible to open the connection again until it was previously closed.
Regards,
Bartłomiej