Need help with connecting MC7355 to Sprint 4G LTE Network - SIM card?

I am trying to replace the functionality of a Netgear LG6100D LTE gateway because of it’s numerous bugs, shortcomings and End Of Life (support) status. I want to use it as a remote link to another property. One of it’s problems is that it drops the 4G LTE connection and will not automatically reconnect the link. So, when the link drops, it’s dead in the water. From the look of the 4G LTE card in the LG6100D, it’s a custom-made Sierra Wireless card rebranded as a Netgear NM7371 card.

I’m trying to get a standard Sierra Wireless MC7355 to work as the 4G LTE radio link of the replacement system.
I have an MC7355 in a WWAN card to USB adapter (with SIM slot). I’ve already successfully updated the MC7355 firmware to the latest Sprint-verified firmware build 4837. (9999999_9902350_SWI9X15C_05.05.63.01_00_SPRINT_005.037_000.exe)
What SIM card model numbers are the “correct” SIM card for the MC7355 on the Sprint Network?
Is there a online database or list that shows this SIM card information?

Yesterday, I moved the current/provisioned SIM card from the Netgear LG6100D into the WWAN card to USB adapter and found that the MC7355 DID connect to the Sprint Network, get an IP address and pass Internet data! But, the data connection only lasts for about 3-4 minutes and then drops. The only way to get it to reconnect is to pull the USB cable, and repower MC7355 card. Then, the MC7355 connects to the Sprint Network again and keeps a data connection for 3-4 minutes, until the connection drops. Repower and repeat cycle.

I contacted Sprint Support via a text chat on their website that they tried to activate the MC7355 but they were unable to get the MC7355 activated so that it would stay connected longer than 3-4 minutes. They suggested I take it into a Sprint store. I seriously doubt anyone in a local Sprint store is going to know what to do with the MC7355 card. I’m guessing one of the first things they’ll do is try and pair it up with the “correct” SIM card, and try again. And, they’ll have to order it from another Sprint location, in another city, so there will be another delay in the process.

So, what is the correct SIM card for an MC7355 on the Sprint Network, and where do we look up that information?

Thanks!
Eric
Minnetonka, MN

Hi @eric.koester

Can you type AT command on MC7355 after it drops LTE network?
Your MC7355 module may be crashed.

Could you please provide some information about the module and SIM card before and after dropping LTE network with the commands below?

AT!ENTERCND=”A710”
AT!BAND?
AT+CGDCONT?
AT!GCDUMP
AT!GSTATUS?

For this readout I’m connecting from Windows 10 and using Putty as my serial software.
Its showing as COM5 at 115.2k BAUD.

Here’s connected to Sprint:

OK
AT!ENTERCND=”A710”
ERROR
AT!BAND?
Index, Name
00, Automatic

OK
AT+CGDCONT?
+CGDCONT: 1,“IPV4V6”,“otasn”,“0.0.0.0”,0,0
+CGDCONT: 9,“IPV4V6”,“cinet.spcs”,“0.0.0.0”,0,0
+CGDCONT: 16,“IPV4V6”,“otasn”,“0.0.0.0”,0,0

OK
AT!GCDUMP
No crash data available

OK
AT!GSTATUS?
!GSTATUS:
Current Time: 88 Temperature: 21
Bootup Time: 0 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B25 LTE bw: 5 MHz
LTE Rx chan: 8665 LTE Tx chan: 26665
EMM state: Registered Normal Service
RRC state: RRC Idle
IMS reg state: No Srv

RSSI (dBm): -84 Tx Power: 0
RSRP (dBm): -112 TAC: AA04 (43524)
RSRQ (dB): -11 Cell ID: 09A1D612 (161601042)
SINR (dB): 0.8

OK

Here’'s after disconnection:

AT!GSTATUS?
!GSTATUS:
Current Time: 1638 Temperature: 19
Bootup Time: 0 Mode: ONLINE
System mode: HDR PS state: Attached
CDMA band: US PCS CDMA chan: 75
Subnet mask: 104 Color code: 32
PN offset: 405
Sector ID: 0084:0AC0:0000:0000:1000:0000:2002:992A
IMS reg state: No Srv

RSSI (dBm): -90 ECIO (dB): -8
IO (dBm): -87 SINR (dB): 6
RX1 (dBm): -87

Here’s the ati command:

Manufacturer: Sierra Wireless, Incorporated
Model: MC7355
Revision: SWI9X15C_05.05.63.01 r28860 CARMD-EV-FRMWR1 2015/07/02 11:04:50
MEID: *********
ESN: ********, *********
IMEI: ****************
IMEI SV: 21
FSN: **************
+GCAP: +CGSM

So, what is the “correct” SIM card for an MC7355 on the Sprint Network, and where do we look up that information?

Thanks,
Eric

Hi @eric.koester

It automatically switches to CDMA network after disconnecting LTE network.
Please check the module signal and SIM card data.

Please contact your reseller or distributor directly in this case.

Hi Donald,

Any idea why there is an error in response to this command?

AT!ENTERCND=”A710”
ERROR

Why A710? Maybe another code will give a valid response?

It automatically switches to CDMA network after disconnecting LTE network.
Please check the module signal and SIM card data.

What does this tell us? The Sprint issued IP address is gone once it disconnects.

Please contact your reseller or distributor directly in this case.

This is a Sierra Wireless forum.
My desire is for someone from Sierra Wireless to answer this one.
Someone from Sierra Wireless MUST know how their devices work.

Please refer this post WE826 with MC7354 did not work with Sprint

Sprint normally uses “otasn” on PDN1 but is is only used by Sprint for over the air provisioning.
Data “n.ispsn” is on PDN3. FW upgrade should take care of that.

Thanks for the thought, ajoseph, but I already covered that base.

From my first post:

I have an MC7355 in a WWAN card to USB adapter (with SIM slot). I’ve already successfully updated the MC7355 firmware to the latest Sprint-verified firmware build 4837. (9999999_9902350_SWI9X15C_05.05.63.01_00_SPRINT_005.037_000.exe)

I got this card used. Maybe I need to reset to factory settings?
Is there is an AT command for that?

Hi eric.koester,

The “A710” is password on my module.
!ENTERCND command
Enable access to password-protected commands
Before you can use any password-protected AT commands, you must enter the password correctly using this command. The initial password is configured onto the modem during manufacture. You can change the password using !SETCND. If you do not know the password, contact your Sierra Wireless account manager.
Once the password has been entered correctly, the password-protected AT commands are available until the modem is reset or powered off and on.

Please refer to AirPrime EM73xx/MC73xx AT Command Reference.pdf for more details.
https://source.sierrawireless.com/resources/airprime/software/airprime-em73xx_mc73xx-at-command-reference/#sthash.jeQzolbu.dpbs

Please try configuring MC7355 with APN “n.ispsn”. You need to provide Sprint the MEID (mobile equipment identifier) to activate it.

This forum is a community of Sierra Wireless module users. The best way to get support is through your commercial channel (i.e who you bought the unit from) in this case.

@eric.koester You can try using AT!RMARESET=RTN to reset SPRINT settings.
SPRINT also ties the modem to the SIM. You will have to contact SPRINT and ensure that your account and modem are setup correctly in their system.

  • Install SPRINT FW. This will setup the correct APNs.
  • AT!RMARESET=RTN (refer the AT guide)
  • Ensure your account is active, SIM and modem are setup correctly by contacting SPRINT
  • Once activated, modem should register properly

If none of this helps, please reach out to your Sierra Wireless or distributor from whom you obtained the modem for support. We will be happy to assist you. Thanks.

I bought this MC7355 unit from a seller on Ebay.
I believe this MC7355 is NOS (new old stock). It was sealed in an anti-stat bag.
(Before I mentioned it was used. I was confusing this with a different card.)

I have not changed any values or passwords inside the unit, other than flashing it with the latest Sprint-approved firmware from the Sierra Wireless site.

AT!GOBIIMPREF?
!GOBIIMPREF:
preferred fw version: 05.05.63.01
preferred carrier name: SPRINT
preferred config name: SPRINT_005.037_000
current fw version: 05.05.63.01
current carrier name: SPRINT
current config name: SPRINT_005.037_000

I just had success with AT!ENTERCND=“A710”
Before I was copying and pasting it into the Putty terminal.
This time I keyed it in character by character.
So, I’m now able to enter password-protected commands!

The SIM card I’m testing the MC7355 with is an active SIM card (activated with Sprint) from the Netgear LG6100D I have, and the MC7355 does connect to the Sprint Network, for about 3 minutes after powerup.

I just tried the AT! RTN command and the ATI command reported modes changed to this:
+GCAP: +CIS707-A, CIS-856, +MS, +ES, +DS, +FCLASS

Before the ATI command reported modes:
+GCAP: +CGSM

AT!PRIID?
PRI Part Number: 9902812
Revision: 01.04

Carrier PRI: 9999999_9902350_SWI9X15C_05.05.63.01_00_SPRINT_005.037_000

I just watched the MC7355 card connect to Sprint. As before, it dropped the connection after about 3 minutes.

SPRINT also ties the modem to the SIM. You will have to contact SPRINT and ensure that your account and modem are setup correctly in their system.

In the first post in this thread I mentioned that I had contacted Sprint Support via chat. The support person entered the MEID & IMEI I gave them, but it didn’t work. They suggested I take it in to a local Sprint store.
I’ve not been impressed with the technical skills of the local Sprint techs. None of them could figure out how to get the Netgear LG6100D properly provisioned, even after they sent me the “correct” SIM card.
I eventually got a support tech on the Sprint Support chat, who knew the LG6100D and directed me to a Settings Reset Button in the LG6100D. It required an MSL code from the Sprint tech to enable that Reset button. That Settings Reset allowed the new SIM card to be linked with the LG6100D. NONE of the local Sprint techs knew they needed to do a Settings Reset of the LG6100D before it would work properly.
I don’t have much hope the local Sprint store techs will know what to do with an MC7355! That is why I’m looking for MC7355 specific help, here.

Maybe I can find some crucial details that I will have to spoon-feed to the Sprint techs?
Maybe the SIM card that works in the Netgear LG6100D isn’t quite right for the MC7355? (Which is why I keep asking WHICH SIM card is the “correct” card to go the an MC7355).

Last night, I discovered that several versions of the MC7355 driver are active in my Windows 10 laptop. I get a different version of the driver loading depending on which USB connector I plug the USB cable into!

The 2016 Sierra Wireless driver (card shows up as MC7355 in Device Manager) does not expose the serial ports of the MC7355, but it does connect to the Sprint network for 3 minutes after you plug it in.

The 2018 Sierra Wireless driver (card shows up as Sierra Wireless Mobile Broadband Network Adapter) and exposes the 3 serial ports of the MC7355. This driver seems to connect to the Sprint network (it gets an IP address assigned) but it does not pass any data, no pings or anything else.

So, I can pick which level of not-working I want by which USB port I plug into!!

When I load one of the Sierra Wireless Driver Package .exe files, it replaces the drivers in the C:\Program Files (x86)\Sierra Wireless Inc\Driver Package directory. With the version I launched. I’ve been using the build 4836 driver set. It appears to be the newest.

=EDIT=

Since this morning, I discovered that there are multiple versions of the drivers that get put into the C:\Program Files (x86)\Sierra Wireless Inc\Driver Package directory.
I tried manually selecting multiple versions of the Sierra Wireless drivers (From the C:\Program Files (x86)\Sierra Wireless Inc\Driver Package directory) by steering the installer to specific inf files in the directory. At this point, NONE of them will expose the 3 serial ports.
I don’t know what happened.

I’m no beginner to computers and Windows drivers and I am totally frustrated with the Sierra Wireless drivers.

By looking at the MC7355 in Ubuntu Linux, I discovered that the card had it’s serial ports shut off - put into a different USB comp mode.
I think it may have been the AT!RMARESET=RTN command.
I was able to use a perl script to change modes to comp 6, which has an open AT port.

> sudo perl swi_setusbcomp.pl -usbcomp=6
> 
> USB compositions:
>    0 - HIP  DM    NMEA  AT    MDM1  MDM2  MDM3  MS      NOT SUPPORTED
>    1 - HIP  DM    NMEA  AT    MDM1  MS                  SUPPORTED
>    2 - HIP  DM    NMEA  AT    NIC1  MS                  NOT SUPPORTED
>    3 - HIP  DM    NMEA  AT    MDM1  NIC1  MS            NOT SUPPORTED
>    4 - HIP  DM    NMEA  AT    NIC1  NIC2  NIC3  MS      NOT SUPPORTED
>    5 - HIP  DM    NMEA  AT    ECM1  MS                  NOT SUPPORTED
>  * 6 - DM   NMEA  AT    QMI                             SUPPORTED
>    7 - DM   NMEA  AT    RMNET1 RMNET2 RMNET3            SUPPORTED
>    8 - DM   NMEA  AT    MBIM                            SUPPORTED
>    9 - MBIM                                             SUPPORTED
>   10 - NMEA MBIM                                        SUPPORTED
>   11 - DM   MBIM                                        SUPPORTED
>   12 - DM   NMEA  MBIM                                  SUPPORTED
>   13 - Config1: comp6    Config2: comp8                 NOT SUPPORTED
>   14 - Config1: comp6    Config2: comp9                 SUPPORTED
>   15 - Config1: comp6    Config2: comp10                NOT SUPPORTED
>   16 - Config1: comp6    Config2: comp11                NOT SUPPORTED
>   17 - Config1: comp6    Config2: comp12                NOT SUPPORTED
>   18 - Config1: comp7    Config2: comp8                 NOT SUPPORTED
>   19 - Config1: comp7    Config2: comp9                 SUPPORTED
>   20 - Config1: comp7    Config2: comp10                NOT SUPPORTED
>   21 - Config1: comp7    Config2: comp11                NOT SUPPORTED
>   22 - Config1: comp7    Config2: comp12                NOT SUPPORTED

Now, the 3 serial ports are back.