MC8705 Network Drop off

We recently received a new batch of MC8705 modems and suddenly experienced network drop offs on the new devices. Typically device would connect to the 3G network and after some time (5mins - some hours) the connection would be dropped and it would not be re-established.

After upgrading to the latest device driver and connection manager builds we found that the WIndows Connection Manager no longer sees the modem so we have to use the Sierra Wireless connection manager.

This seems to have partially fixed the problem and we have seen only one device drop off the network and not connect again in the last 12 hours of testing. As far as I can tell we have the configuration set for autoconnect and we have the connection manager set to autostart. Seems the autostart works fine but the connection drops after some time and fails to re-establish.

Has anyone else experienced this issue and if so are there any solutions for re-establishing the network connection? We have an application running so we can call an API to reconnect if such an API exists.

Any help would be appreciated.


A few questions.

  • You mentioned a new batch. Does this mean you have received units in the past which have worked properly and do not drop off the network at all?
  • When you say drop off the network do you mean lose it completely or fail to start a session?
  • Windows is mentioned, is this what you system is based on or are you using this for testing?
  • What versions of watcher/skylight are you using and what firmware version do you have in the MC8705’s? Also what driver release are you installing?
  • For information what networks are you using?

If you can answer the above it might help me to provide a bit more feedback.



Initially we received two Arbor ELIT-1200 PC’s with two MC8705 cards.

The PCs have Win 8.1 Embedded Industry Pro 32 bit and run a custom application as the shell.

We installed the which seems to install the device driver and the Watcher. We were able to use the Windows Connection Manager set to Autoconnect with these devices and this version of the software.

While we had quite a fews comms errors we worked around this by retrying when we got communication exceptions while trying to perform network activities. We retry 3 times before aborting the attempt and there seemed to be only very infrequent occasions when retries failed.

We subsequently ordered a new batch of PCs with 3G cards from Arbor and immediately ran into problems with the PC dropping the network connection and not re-establishing it.

Dropping the connection means that one cannot access the internet so any internet connection attempt results in an error. If you manually select Connect in the Windows Connection Manager then the connection is re-established and things work for a while.

These drop outs typically occurred within 5 or 10 minutes of establishing a connection.

In order to try and fix this we then downloaded and installed the latest AirPrime drivers and Sierra Wireless Connection manager. Files are:

  • Build3795_DriverInstaller_DIP.exe
  • Watcher_Generic_Build_3830.msi

Windows Connection manager was no longer able to see the Mobile Connection after installing the Build3795_DriverInstaller_DIP.exe so we had to use the Sierra Wireless Watcher.

This Watcher has a popup window in the lower right hand side of the screen that appears whenever it connects to the 3G network, this is undesirable for us because we are running a KIOSK application.

This substantially improved the drop off issue, however it still happens occasionally, and sometimes quite frequently. The only way to re-establish the connection is to manually select Connect on the Watcher or to reboot the PC. Obviously for a kiosk application this is not acceptable.

I have no idea what firmware version is on the cards - how can I determine this and how can we upgrade the firmware if that is required. I have been unable to find any reference to doing this on the Sierra Wireless web site.

We are using Optus (Australia), might be an idea if we test using a Telstra or Vodafone sim card…

So we have 3 issues we need addressed:

  • new MC8705 driver should work with Windows Connection Manager, it does not display a popup when creating the connections
  • Sierra Wireless Watcher should not display a popup when connecting - this is for embedded devices. Alternately provide some configuration option to suppress them. Note that we do no use Windows Shell, we use Embeddedlockdown Manager to launch an application shell so we can’t use Notification settings to disable popups (not that this prevents the popups from displaying anyway)
  • Network drop offs should not happen, and if they do connection manager should re-establish the connection

We are also wondering whether the quite frequent comms exceptions we are getting may be a device driver issue.

And finally are there any API’s our application could call to better manage connections?



Windows 8, tough one, the PC OEM boys had alot of issues integrating with this, due to the way they have implemented MBIM. Technically none of our drivers are rated for Win8 yet and I do not think we

Anyway regarding the issue, I suggest we cut watcher out of the equation, that will get rid of the icon icon in the bottom right corner so just install the drivers. Then do the following (I will have to walk through froma win7 perspective as I do not have a win8 machine)

  1. Go into ‘Devices and printers’.
  2. Roght click to look at the properties and the ports that have been created, one of these should be an AT command port ‘comX’.
  3. Run aa terminal program i.e. teraterm, procomm, hyperterminal and connect to to the port so that you can send AT commands.
  4. Send the below commands to the unit
ati                    //This will give you all the ionformation about the unit including its firmware version
at+cgdcont?            //This tells you the APN's that are set up on the unit and which you connect to the network through, note the first number of the APN you want to use.
at!scprof=x,"Connection",1         //This sets the default connection for the unit where, x is account from the above step,, "Connection" can be anything as long as its in "", 1 sets the connection to auto connect which means the firmware will always try to maintain the connection if possible, watcher just sets this parameter (albeit through a different interface).

So things to check for you I would suggest are

  1. Test on another network.
  2. The different firmware versions between the units.

If after this you are still experiencing issues then it will be a driver issue but very difficult to fix, because its windows 8. You would then need to go back through your commercial channel.



OK, thanks I will look into it as you suggest. Any timeframe for win 8 drivers ? Perhaps you might even suggest an alternative card we could consider using ?

BTW if we do find its different firmware versions what would we need to put the same firmware on all cards ?


Win 8 is a difficult one as you cannot have ‘generic’ drivers anymore, to work with MS you have to confirm to their MBIM interface which is hard (it is supported in the MC73 series) and is not a simple task as it requires not only firmware but applications adhere to it. For normal customers (not PC OEM’s who we have SLA’s with and write specific code for), short answer is, no, no time lines to win 8 drivers.

Re the firmware if you have bought through an official channel then what you have is almost certainly ok. You will need to ping them to discuss what you have and what is available. The latest approved firmware is also available through the dev zone.



You say it is supported in the MC73 series - so is there any reason we can’t use the MC73 series cards ? Would that give us supported drivers ?


I stick to my previous answer, Windows 8 can only be truly supported by us through using the MBIM interface and going through subsequent MS certification with an application (which we do with the PC OEM’s), we cannot offer ‘generic’ Windows 8 support as this is not the way MS have built it. The basic position we have with our drivers at the moment is as below.

  • Windows XP supported
  • Windows 7 32bit supported
  • Windows 7 64bit supported
  • Windows 8 might be functional but we do not officially support it hence any issues would need to be reported back through your commercial channel and we would address it in due course depending on its severity and business that was at stake.

You can move to the MC73 and I would recommend it since the MC77 series is EOL but as to using the MBIM interface not necessarily a good idea, you need to be technically well versed to do this.



Matt, thanks for the reply, can you confirm what you mean by the following:

  • ‘going through certification with an application’ - what do you mean by application here, would this be our kiosk application or the connection manager? Our application just uses Web Services over the internet, it has no need to interact with the modem itself.

  • We are using MC8705 not MC77 series, is the MC8705 also EOL ?

Matt, here is the output I am getting.

Manufacturer: Sierra Wireless, Incorporated
Model: MC8705
Revision: T1_0_1_1AP R309 CNSZXL00000015 2011/01/21 18:28:30
IMEI: 353567040885429
FSN: CC32842114610
3GPP Release 7


+CGDCONT: 1,"IP","","",0,0
+CGDCONT: 2,"IP","connect","",0,0
+CGDCONT: 15,"IP","connect","",0,0






Am I doing something wrong with the at!scprof command ?

BTW I just uninstalled the Watcher and things keep working. So I install the device driver then the watcher, set things up and then uninstall the watcher and it keeps working without the popup.

If I now use the Browser to connect to the internet the first time I try the browser reports a network error but subsequent tries work. Is this expected behaviour where the modem will only establish a connection when an application tries to reach the external network ?

If so should we do some dummy network calls from our application to force a network connection to be established or should things just work ?


Alot of things there to answer.

Re the MC8705, it will be going through a respin in the near future because of EOL of some components but your channel should advise you of this. Effectively this will be transparent to you.

Re the position on the drivers bit of other feedback from a different product manager (its all a bit smoke and mirrors), in theory the unit drivers we supply should work with Windows 8 and any issues need to be reported back through the commercial channels which will be what you need to resort to. I would ignore the MS certification and MBIM comments they are just going to confuse things.

Re resolving your issue.

  1. Do you know the APN you want to use? If so set it with the at+cgdcont command as I previously detailed, set the default connection and the auto connect parameter. Below are the commands from my unit, to get the command o be accepted you need to include all of the parameters.
+CGDCONT: 1,"IP","orangeinternet","",0,0
  1. Re it not starting up a connection until you tried access services, this is not normal and with auto connect on it should start a session as soon as it attaches to a network.



Matt thanks for your help, we have a lot of comms errors using this modem which we don’t see using a Optus provided USB modem (Hauwei 3276). Their drivers seems to load correctly.

Until we can get some driver fixes we will have to look for an alternative modem.

The driver seems to load but connections seems to struggle a bit with lots of errors and much retry code in the app to ensure transactions complete.

Matt, well further testing seems to show that other hardware devices (3G cards) also drop off the network and fail to re-establish the connection until the device is restarted.

Would it be possible for force a “Connect” by sending the modem an AT command and if so what are the commands to use.

It seems like Windows thinks the modem is connected but the internet is not available so we probably need to send the modem some commands to reset and reconnect or something. As far as I can tell simply hitting “Connect” in the watcher re-establishes the connection.

Our app already controls 4 other serial port devices so it would be relatively easy to do this.

Thanks for any assistance here - some pointers to a programming guide for beginners would be useful too as we have no real knowledge of controlling a 3G card to establish and maintain network connections!

OK so further testing seem to show that the problem occurs in areas where 4G signal is weak but the 3G signal is strong and the modem tries to connect with HSPA+ and fails and then gets hung up trying to drop down to a lower speed protocol.

I can’t find any way to prevent the modem from using anything other than 3G connection. AT!RESET gets the modem to connect again but it then starts trying to use a high speed connection and gets hung up before it gets to connect at a lower speed.

We don’t need speed but we do need reliable connections so perhaps even a 3G only modem might solve the problem. Seems like a firmware update required on the modem to prevent this hangup.

To close this off - I finally managed to track down a firmware update which seems to have addressed the comms errors and network drop offs.

Very disappointing that no-one from Sierra Wireless pointed out that a new firmware version was in fact available.

FYI this firmware is dated 2014-07