What to do when no signal


#1

Hi
I am currently using gprs to put some data on a http server. Everything is ok. The problem is that i have no way of knowing remotely if a device has gsm signal or it hasn’t. I mean is there a way to notify me or do something so i know that the device has no signal, or signal is lost, then regained. All of this must be done remotely, the device is out there somewhere in the field.
Thanks


#2

The unit can determine whether or not it has GSM and GPRS service by enabling and monitoring +CREG AND +CGREG unsolicited responses.
You may also want to monitor +CSQ.

Obviously, the remote unit cannot notify that it has lost connection! 8)


#3

:slight_smile: Well i am doing those thing you said :slight_smile: But what i what to do is to notify that the connection is lost :slight_smile:(A bit silly i know when you put it like this) I was hopping there is some clever way to do this


#4

If you have no signal, you have no service - so there is no way to notify anything at all - obviously!

Perhaps you could implement some kind of “heartbeat” - if your “server” stops receiving the “heartbeat”, you assume that the remote unit has lost its connection.

Or you could try to find a service provider that can indicate when units have lost contact with the network.

Or you could provide some kind of backup path to signal when the main path has failed

etc, etc,…


#5

awneil’s suggestion of a heartbeat is probably the easiest for your to implement - it’s the method I use too.

All our units are expected to regularly log in at a known time. If they don’t, something has gone wrong. Easy!


#6

What about the path described below:

Server knows that modem have to connect in certain time. If there was no connection, server calls to modem tel number and check the response. It needs modem (or device that can make a call) on server side.


#7

But if there was no connection, it was because the modem had no GSM service - so it would not be able to receive the incoming call, would it?!