EM7455 transmitting AT commands without requesting them

#1

I have an EM7455 that was given to me by a coworker. I am using the Sierra dev kit. I connected to the kit using minicom on Debian and noticed that there are AT commands coming out periodically from the EM7455 with requesting them. One of them is the CSQ (Signal Quality). I like this feature and I would like to have other AT commands automatically come out of the EM7455. Is this a timer feature? How do I get these AT commands to send automatically?

#2

most likely modemmanager app is sending those AT commands.
the modem only sends unsolicited notifications - these must be previously subscribed

#3

I thought I turned off the modem manager. Can you confirm that I am supposed to turn it off?

#4

Depending on what you want to do.
if you want to control the modem by yourself, then yes you should disable modem manager.

#5

I am using an EM7455. It has the Sprint firmware. I am having issues getting the correct virtual IP address from the host. I thought it could be some conflicts with the modem manager. Have you ever seen where people get the wrong IP address when they write AT!SCACT=1,1? I need a way to prove to Sprint that it is their network problem.

Tim Curry

#6

Hi Tim,

“Have you ever seen where people get the wrong IP address when they write AT!SCACT=1,1”
No I did not.
You don’t need modem-manager to verify the IP address on LTE.
When the modem is powered up, it initiates a combined EPS/attach procedure. The modem will attach to LTE and obtain an IP address in the same time.
You can verify this IP with at+cgcontdp

At!scact=1 will establish the session between the host and the modem. Since PDN1 IP is already available then modem doesn’t need to send a session req. to the NTWK.
In other words at!scact=1 will not trigger any OTA messaging.

Thanks,
James