Hello,
We have a DT85M.

We have a job which sends every 24h a SMTP email.
As the carrier is T-mobile, we set in the code APN as following:
PROFILE MODEM APN="epc.tmobile.com"

We want to use the same job but using a SIM from another carrier, AT&T.
The phone subscription is data only (we cannot send text or call).
The only modification in the code should be the APN, to correspond to AT&T:
PROFILE MODEM APN="i2gold"

However, it doesn't work :
After few minutes without suceed, the DT85M display shows "Modem will retry [comms problem]"

With put P56=16, we can see the modem cummunication:
SESSION: Starting (manual)
MODEM: absent
MODEM: power on
MODEM: detected
MODEM TX:
AT&D1&C1E0&W
MODEM RX:
OK
MODEM TX: AT+CGMM
MODEM RX:
MODEM RX:FXT009 Product
MODEM RX:
OK
Modem type unknown 1
MODEM TX: AT
MODEM RX:
OK
MODEM TX: AT+CMEE=1
MODEM RX:
OK
MODEM TX: AT+CPIN?
MODEM RX:
+CPIN: READY
MODEM TX: AT+CIMI
MODEM RX:
3104xxxxxxxxxxx
MODEM RX:
OK
MODEM TX: AT+WMBS?
MODEM RX:
+WMBS: 7,0
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+COPS=0
MODEM: power off
SESSION: Failed [Comms problem] - will retry

Any idea of the cause ?

Hi David,

Multiple AT+CREG? with a result of 0,2 indicates "not yet registered and the modem was not trying to register" to "UTRAN (other name of 3G) network".
The modem could be busy in booting up period or something else holding the modem.

Also in some cases, SIM with data subscription only have failed registration tendency if it is being used with 3G modem (not with mobile phone or tablet).
Because some base station may give different response during registration to this type of SIM card thus the modem will assume a failed connection due to incorrect response.

There are two possible solutions:

• increase registration time from 60 to 65 seconds (PROFILE MODEM REGISTRATION_WAIT_S=65)
• change the SIM card to allow a full functionality (include text and voice)

Best regards,
Rudy Gunawan

Hello Rudy,

Thank you for your reply.

I tried today both solutions you proposed:

• increase registration time from 60 to 65 seconds (PROFILE MODEM REGISTRATION_WAIT_S=65) => That doesn't solve the problem
• change the SIM card to allow a full functionality (include text and voice) => That doesn't work neither. Yet, we took an AT&T SIM card which works for sure, with a unlimited text/voice/data subscription

Do you have other suggestions that we could try ?

Regards,
David RIFF

Hi David,

Please check modem diagnostic for any new error message after applying those two solutions.

Best regards,
Rudy Gunawan

Hi Rudy,

We applied the 2 solutions to the DT85M:

• use AT&T with a full subscription: text, call and data
• use a registration time of 65 instead of 60 (default value)

This is the result that we have for the modem communication:
SESSION: Starting (manual)
MODEM: power on
MODEM: detected
MODEM TX:
AT&D1&C1E0&W
MODEM RX:
OK
MODEM TX: AT+CGMM
MODEM RX:
MODEM RX:FXT009 Product
MODEM RX:
OK
Modem type unknown 1
MODEM TX: AT
MODEM RX:
OK
MODEM TX: AT+CMEE=1
MODEM RX:
OK
MODEM TX: AT+CPIN?
MODEM RX:
+CPIN: READY
MODEM TX: AT+CIMI
MODEM RX:
3104xxxxxxxxxxx
MODEM RX:
OK
MODEM TX: AT+WMBS?
MODEM RX:
+WMBS: 7,0
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+CREG?
MODEM RX:
+CREG: 0,2
MODEM RX:
OK
MODEM TX: AT+COPS=0
MODEM: power off
SESSION: Failed [Comms problem] - will retry

It is similar to what we have before.
It seems that it could be because of the carrier, do you think that can be the reason ?

David

Hi David,

Could you check this dataTaker modem through TEST command?
Assuming this is GSM modem model (2G - DT80LM2-3) then you can't use AT&T SIM as AT&T network is no longer support 2G.

If that is true (about DT model), there are a couple solutions:

• Contact our USA distributor and get a replacement modem (that support 3G)
• Use an external modem that support 3G (preferably 3G router)
• Use Verizon (as this network will be retired in 2021).

Best regards,
Rudy Gunawan

Hello Rudy,

We have a DT85M datalogger with a FTX009 modem, so I suppose it it a DT85M2 ?

You are right, AT&T stopped the 2G in 2016.
It seems that FTX009 support only 2G and NOT 3G so that clearly could be the root cause of our problem :)

The FX100 does support 3G
Does the FX100 is fully compatible and could replaced the FXT009 without any other change ?
Is it compatible about mechanic, software and hardware ?
If not, do you have another solution about that ?

Best regards,
David

Hi David,

Do you plan to use FX100 module and replace the existing modem module FX009 (inside the logger)?
If yes, there are some preparation to do that mostly firmware upgrade for both logger and modem to match current version.

Other option would be using 3G router through Ethernet connection.

Best regards,
Rudy Gunawan

Hello,

We did a modem upgrade (our supplier did the modem installation and testing): FXT009 (2G) replaced by FX100 (3G).

So we tried to connect with the T-mobile SIM card (with the old modem, it was already working with this SIM): we do can connect, and we can see "H" on the display which shows that we have more than only 2G.

We did the same with the AT&T SIM card (call+text+data full subscription): it still doesn't work.
However, this time the result is different:

• Before: We never saw that the system could connect to the network (indeed we had a 2G only modem so we couldn't connect)
• Today: the system tries to connect (and with P56=16, we can see the modem messages are similar than with the AT&T SIM) but when it reaches to connect, less than 1s after, the system displays "Closing". Then we get "Failed [Data dropped] - will retry" If we try again, we have the same scenario but finishing by error "Failed [Data dropped] - will retry". If we start the comm a 3rd time, we get: "Failed [Network check] - will retry"

I tried that with PROFILE MODEM APN="i2gold" and with PROFILE MODEM APN="". Both don't work.
Is there something special to configure with AT&T SIM cards ?

David

Hi David,

Please increase register time in profile setting, it may need longer time to register (default is 60 seconds, increase to 65 seconds).
PROFILE MODEM REGISTRATION_WAIT=65.

If it does not work, please enable network diagnostic P56=32. It will create 2 pcap files in a new DIAG directory.
Try a couple of attempt to connect to 3G, then disable network diagnostic P56=0.
PM me those files.

Best regards,
Rudy Gunawan