"warning: alarm synchronization problem" when trying to pppd gprs call

[miguel.agfreitasParticipant]

After following all the instructions on the tutorial, whenever I try to pppd gprs call, the script prints ‘^@’ over and over again and 30 seconds later I get “warning: alarm synchronization problem”. I could not find anything relevant on the internet. Is there anyone here that can help me?

[mnelsoneormParticipant]

Same problem here.

[mnelsoneormParticipant]

Same here. Wondering if the connection script needs some sort of update. Tried on PiZero(older non-w) and couldn’t get it to work at all. Switched to a Pi3 and have the same sync error and hundreds of ^@ before finally disconnecting.

[mnelsoneormParticipant]

Arg…previous replies still not showing up…try again….

Same problems here. Hundreds of ‘^@’ and then disconnect and sync error.

[mnelsoneormParticipant]

Also finding that minicom can’t talk to it. Also, pressing the power button for two seconds starts the blue light flashing if powered by itself over USB but attached to the Pi I cannot get the blue light to flash either via power button for two seconds or by setting GPIO25 high for two seconds.

[mnelsoneormParticipant]

Ok, not sure why they’re not making this information more “in your face” but apparently some of the boards have a manufacturing defect and pin 20 shouldn’t be connected. I have a stacking header between the shield and the pi so I just bent pin 20 away and put the shield back on. Power the shield and run the script – connects just fine now. I found this info in the post regarding sending SMS. This information needs to be front and center and not buried in some unrelated post.

[MetinKeymaster]

Hi,

Please power up module firstly.

[Author]

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