GPRS Roaming

Legacy Open AT
1

During a test with a unit travelling through Europe, we came across an odd issue.

  1. Unit had GPRS and TCP connection to a server through Sweden, Germany and Belgium, but when it reached France, the connection disappeared.
    Checking with the unit, it had CGREG indicating roaming, but AT+CGACT=1 returned an ERROR (in this case +CME ERROR: 134)
    While in France it had +COPS: 0,2,20801

  2. Unit had GPRS and TCP connection to a server through Sweden and through half of Germany when it lost connection.
    Checking with the unit, it had CGREG indicating roaming, but AT+CGACT=1 returned +CME ERROR: 3
    Unknown what operator the unit had while it was connected and after it lost connection.

We checked with the operator (Telia) and they are supposed to work with GPRS in either of the cases.

Unit was equipped with a Q2687RD with R7.44 firmware.

Any ideas?

2

What does that mean?

3

+CME ERROR: 134
service option temporarily out of order (#34)

Which really doesn’t say much at all considering the tendency of network equipment to differ in how they map errors to error codes.

4

It tells you that it should work, but there’s a fault at the moment - so it’s worth re-trying “in a while”

As distinct from just refusing because it’s not allowed or not supported - in which case re-trying would be pointless.

5

I know that it “should” work, and it was attempted several times during two days.

What I meant with that it doesn’t say much is that there is a tendency from equipment manufacturers to lump “no clue what is wrong” with “try again later”.

6

I have seen the same problem with q2686’s crossing the beglian/french border.

I have heard this, from a contact from our (M2M) telephony provider. It might not be entirely accurate so consider it as a guess:
Operators could reject attempts to connect to a foreign operator with whom your own operator has a less favorable roaming agreement.
In other words they prefer if you use a different operator in that country, so they might reject the few first attempts.
Have you tried reconnecting between 5 to 10 times in a row? Please let me know the results.

Do you also detach properly from the network when you restart your unit?

7

Testing with firmware R7.46 now.

There is one case that we can’t get rid of.

+CGREG: 2,5,"…","…"
+CGATT: 1
+CGDCONT: 1,“IP”,“apn”,0,0

AT+CGACT=1,1
+CME ERROR: 3

SIM-card is from Telia (swedish operator)
Network tested on in Germany:
+COPS: 0,2,26201 (Telekom Deutschland GmbH)
+COPS: 0,2,26202 (Vodafone)
+COPS: 0,2,26207 (O2 (Germany) GmbH & Co. OHG)

Another unit with SIM-card from Telia, using exact same firmware and software, works fine in the same areas tested. IMEI numbers for the two units belong to the same range…

8

We’re suspecting that it’s a SIM-card related issue.
The physical SIM-cards are from different batches from the operator.
The SIM-cards between the working and non-working unit will be switched to see if the issue follows the SIM.

9

According to the last information we have received from the operator, they are suspecting a problem in a HLR en.wikipedia.org/wiki/Network_sw … _.28HLR.29
and are investigating now…