Handling "Limited Up" modem state | Telit Cinterion IoT Developer Community
March 13, 2018 - 10:21am, 1529 views
In GPRS TCP/IP connection what is the correct way to handle "Limited Up" modem state?
(Internet connection is established, but temporarily no network coverage)
Do I need to constantly pull for "Up" state to resume?
Do I need to issue a Service/session close and open when I got "Up" state?
Or do I only need session open when state reaches "Down" then "Up"?
Can I get away without network state polling? (registered, searching..)
Is there a good flow diagram about connection fallback/escalation handling?
My particular modem is BGS2-W, but I think this is generic.
Can you describe a typical scenario when you get into this situation? Is it happening frequently? Any log available? Is the network coverage poor? Have you checked the network registration status or AT+CEER output?
I'm writting the driver for the modem and the datasheet mentions this possibility, so I have to be prepared for it.
This status means that the network connection was lost. So if you have enabled network registration status URC with AT+CREG=2 you will get +CREG: 2 when it happens. If the network will not be back in a short time you will probably need to close the service.
But if you are going to use the module as modem you will not be interested in this particular command as it's for the profiles created with AT^SICS command which are used for Internet services over AT commands created with AT^SISS command. With these services you can create socket, http, ftp, smtp, pop3 connections and transfer data with AT commands. You will probably want to just create a dial-up PPP connection.