MC7304 Not GPRS Attaching

IoT Modules MC/EM Series
1

We are trying to integrate an equipment using MC7304 as a Modem.

We can confirm that it can work and attach with the local public networks using LTE (i.e., Telstra or Vodafone).

When using it on a private 2G network, we can confirm it sees the base station but it’s not successfully registering.

Have tried upgrading the modem’s firmware with the latest Generic version (instead of Telstra), it can see the 2G network now when issuing AT+COPS=? command but still unsuccessful in GPRS / PS attaching.

Based on AT!GSTATUS?, the following is the result:

!GSTATUS:
Current Time: 97 Temperature: 35
Bootup Time: 5 Mode: ONLINE
System mode: GSM PS state: Not attached
GSM band: DCS1800
GSM channel: 872
GMM (PS) state: DEREGISTERED ATT NEEDED
MM (CS) state: IDLE UPDATE NEEDED

Serving cell: 864 (GSM 1800 )
RX level (dBm): -73.7350 LAC: 0068 (104)
GPRS state: GPRS IDLE Cell ID: 00002BD5 (11221)
OK

Can also confirm AT+CGDCONT as correct.

2

@anthonynanas101,

Given its a private 2G network, I am presuming you are using a SIM for that private network with the correct authentication details?

You could try manually selecting the network with the below.
at+cmee=1
at+cops=1,2,“xxxxx”,0 where xxxxx is the MCC/MNC for the network

This would at least give you an error cause to work with, remember to set the unit back to auto mode afterwards (at+cops=0).

BTW you do not need an APN set through at+cgdcont to attach to 2G or 3G.

Regards

Matt

3

Hi Matt,

Thanks for responding and helping out.

I get a CME Error 30: which is “No network service”

This is confusing as I can confirm that the SIM card would work on another device using another Modem (HL7692). And When I issue AT+COPS=? it can see the network as well.

4

@anthonynanas101,

Yes it can come back with this if it has been rejected by the network as from its point of view it does not have a network to connect to but thats down to the language used in the spec’s.

Regards

Matt

5

Hi Mike. Can you elaborate on this?

Does that mean that the modem isn’t compatible with the network or can I take this with the network provider and get support and understanding on why it’s being refused. The engineers on that side can verbally confirmed that they don’t have IMEI blocking but this results is telling me otherwise.

Does Sierra Wireless have a protocol tracing software tool so I can prove it’s the network causing the rejection?

6

@anthonynanas101,

Assuming you can see the 2G network its probably going to be a SIM rights issue, you have mentioned Telstra, there is no 2G in Australia any more so I am surprised.

Can you post the actual responses from the unit to the below?

ati
at!priid?
at+cimi
at+cops?
at+cops=?
at+cops=1,2,“xxxxx”,0

Regards

Matt

7

Hi Matt,

Thanks. How do I confirm if it’s a SIM rights issue? That would be weird as the SIM works on another equipment with a HL7692 Modem. The 2G network is a private telco used for GSM-R so don’t be surprised, you would know how the rail industry takes forever to move and transition to the latest and greatest.

ATI_PRIID COPS QUERY
ATI_PRIID COPS QUERY675×540 17.5 KB
COPS

8

Do note that I have forced the modem to only do 2G, thus it’s not seeing the other LTE signals anymore from Telstra, Optus and Vodafone here.