3G/LTE modem configuration failure (Sierra Wireless MC7700)



  • I'm working to get my pfSense 2.2 installation recognizing and using a Sierra Wireless MC7700 card on a pcEngines APU system.

    I managed to get the card changed to DIP mode (having to install Windows to do it), and now the pfSense box sees the card successfully as cuaU0.0 - cuaU0.5.  (Thanks to the post https://forum.pfsense.org/index.php?topic=87908.msg515972

    I have found that cuaU0.3 and cuaU0.4 both seem to accept AT commands (via logging under System Logs > PPP) while the other 4 will not.

    However, both of those ports report "Invalid dial init string."

    Sep 4 00:12:42 	ppp: [opt4_link0] Link: reconnection attempt 355 in 3 seconds
    Sep 4 00:12:42 	ppp: [opt4_link0] LCP: Down event
    Sep 4 00:12:42 	ppp: [opt4_link0] Link: DOWN event
    Sep 4 00:12:42 	ppp: [opt4_link0] MODEM: chat script failed
    Sep 4 00:12:42 	ppp: [opt4_link0] CHAT: Invalid dial init string.
    Sep 4 00:12:42 	ppp: [opt4_link0] CHAT: ATD*99#
    Sep 4 00:12:42 	ppp: [opt4_link0] CHAT: Dialing server at *99#...
    Sep 4 00:12:42 	ppp: [opt4_link0] CHAT: Detected Hayes compatible modem.
    Sep 4 00:12:42 	ppp: [opt4_link0] CHAT: +CGDCONT=1,"IP","pta"
    Sep 4 00:12:42 	ppp: [opt4_link0] Link: reconnection attempt 354
    

    Note the "ATD99#" dial string.  I found another post a year ago (https://forum.pfsense.org/index.php?topic=71012.0 that had the same problem with the default string of "ATDT99#" and the recommendation was the change it to ATD from ATDT.

    I traced the init scripts and found that that prefix was set in /etc/inc/interfaces.inc under "$DialPrefix" as DT, and I changed it to D.  The problem persists, with the only difference in the log being "ATD" as opposed to "ATDT".

    What could I be missing?  I know other people have gotten this card to work, and I'm totally blocked.

    Thanks in advance!



  • One more thing…  when I reboot the system, the ppp subsystem doesn't even try to come up.  The /var/etc/mpd_opt4.conf file doesn't exist.  When I go into the UI, click save on the PPP config, the file pops up and it tries to connect (with the results as seen above).



  • I think something has changed for the USB port settings as you have noticed. Seems that MC7700 is now showing up as cuaU0.3.. Just for testing - please try an earlier version of pfSense and use cuaU0.4 if you can…<=2.2.2



  • I'm actually on pfSense 2.2-RELEASE; I haven't upgraded beyond that yet.  What version were you on when you managed to get it working?



  • And one more puzzling thing I've found.

    When I'm using ppp > term, or cu, the card responds "OK" to AT, and tons of AT commands.  But the only command I've found that it actually will give data is:

    AT+COPS?  (which is supposed to return the current network operator)

    which returns with

    +COPS: 0,0,"Limited Service",2

    I looked at the supported AT commands from Sierra (http://source.sierrawireless.com/resources/airprime/minicard/2130617_ac_ap_umts_supported_at_command_reference/) and tried many of the commands to look at available networks or firmware version, or SIM status, and they all just respond "OK".

    Trying ATD*99# gives only "ERROR".

    The only box I have with a SIM slot is this APU, which of course can't run windows as there's no VGA.  So I've ordered a SIM adapter to use in the windows machine I originally flashed the card with.  That's my next troubleshooting step unless someone has something else I can try.



  • I think it is a good idea to get it running under Windows with the Sierra Watcher working first..I can help more this weekend.



  • I really appreciate it.

    I've never worked with modems under *nix (and other than clicking "go", not in windows either), so this is all brand new.  I can figure out just about anything with source code when it's software only, but hardware just doesn't work in my head.

    I'll have the SIM adapter on Sunday, according to Amazon.



  • So let me know if this is a new module or used. If used you may have to do a complete reset and calibration.
    Regardless the newest firmware is a must. So at least lets try and figure out what your firmware is. Try this command at AT prompt.
    ATI
    We are looking for the –SW9300-- part for the firmware revision.

    If your ATI command returns real basic info including a line "APP1" then you are on the wrong command port. Try some more ports..
    If on the correct port ATI command will show the firmware version.

    Also try and run this for info:
    AT!UDINFO?

    If on older firmware will not work. They have upgraded their extended AT commands since the module came out in 2012.

    Since on console only you need the adapter to proceed.

    Have you tried AT!BAND?
    http://forums.whirlpool.net.au/archive/1674939



  • You really should be using APN of "broadband" for att.

    Here is my ppp log. My device is on cuaU0.3

    Sep 6 09:40:29 	ppp: [wan] IPCP: SendConfigReq #2
    Sep 6 09:40:29 	ppp: [wan] IPADDR 0.0.0.0
    Sep 6 09:40:29 	ppp: [wan] COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
    Sep 6 09:40:29 	ppp: [wan] PRIDNS 0.0.0.0
    Sep 6 09:40:29 	ppp: [wan] SECDNS 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] IPV6CP: SendConfigReq #2
    Sep 6 09:40:30 	ppp: [wan] IPCP: rec'd Configure Nak #2 (Req-Sent)
    Sep 6 09:40:30 	ppp: [wan] IPCP: SendConfigReq #3
    Sep 6 09:40:30 	ppp: [wan] IPADDR 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
    Sep 6 09:40:30 	ppp: [wan] PRIDNS 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] SECDNS 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] IPCP: rec'd Configure Request #1 (Req-Sent)
    Sep 6 09:40:30 	ppp: [wan] IPCP: SendConfigAck #1
    Sep 6 09:40:30 	ppp: [wan] IPCP: state change Req-Sent --> Ack-Sent
    Sep 6 09:40:30 	ppp: [wan] IPCP: rec'd Configure Reject #3 (Ack-Sent)
    Sep 6 09:40:30 	ppp: [wan] COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
    Sep 6 09:40:30 	ppp: [wan] IPCP: SendConfigReq #4
    Sep 6 09:40:30 	ppp: [wan] IPADDR 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] PRIDNS 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] SECDNS 0.0.0.0
    Sep 6 09:40:30 	ppp: [wan] IPCP: rec'd Configure Nak #4 (Ack-Sent)
    Sep 6 09:40:30 	ppp: [wan] IPADDR 10.138.91.43
    Sep 6 09:40:30 	ppp: [wan] 10.138.91.43 is OK
    Sep 6 09:40:30 	ppp: [wan] PRIDNS 172.26.38.1
    Sep 6 09:40:30 	ppp: [wan] SECDNS 172.26.38.2
    Sep 6 09:40:30 	ppp: [wan] IPCP: SendConfigReq #5
    Sep 6 09:40:30 	ppp: [wan] IPADDR 10.138.91.43
    Sep 6 09:40:30 	ppp: [wan] PRIDNS 172.26.38.1
    Sep 6 09:40:30 	ppp: [wan] SECDNS 172.26.38.2
    Sep 6 09:40:30 	ppp: [wan] IPCP: rec'd Configure Ack #5 (Ack-Sent)
    Sep 6 09:40:30 	ppp: [wan] IPADDR 10.138.91.43
    Sep 6 09:40:30 	ppp: [wan] PRIDNS 172.26.38.1
    Sep 6 09:40:30 	ppp: [wan] SECDNS 172.26.38.2
    Sep 6 09:40:30 	ppp: [wan] IPCP: state change Ack-Sent --> Opened
    Sep 6 09:40:30 	ppp: [wan] IPCP: LayerUp
    Sep 6 09:40:30 	ppp: [wan] 10.138.91.43 -> 10.64.64.0
    Sep 6 09:40:31 	ppp: [wan] IFACE: Up event
    Sep 6 09:40:31 	ppp: [wan] IFACE: Rename interface ng0 to ppp0
    Sep 6 09:40:32 	ppp: [wan] IPV6CP: SendConfigReq #3
    Sep 6 09:40:34 	ppp: [wan] IPV6CP: SendConfigReq #4
    Sep 6 09:40:36 	ppp: [wan] IPV6CP: SendConfigReq #5
    Sep 6 09:40:38 	ppp: [wan] IPV6CP: SendConfigReq #6
    Sep 6 09:40:40 	ppp: [wan] IPV6CP: SendConfigReq #7
    Sep 6 09:40:42 	ppp: [wan] IPV6CP: SendConfigReq #8
    Sep 6 09:40:44 	ppp: [wan] IPV6CP: SendConfigReq #9
    Sep 6 09:40:46 	ppp: [wan] IPV6CP: SendConfigReq #10
    Sep 6 09:40:48 	ppp: [wan] IPV6CP: parameter negotiation failed
    Sep 6 09:40:48 	ppp: [wan] IPV6CP: state change Req-Sent --> Stopped
    Sep 6 09:40:48 	ppp: [wan] IPV6CP: LayerFinish
    
    


  • Here is working ppp.conf for MC7700 and ATT that I am using with FreeBSD 10.2 with OpenDNS. This is for troubleshooting modem and connection. You should use Windows to flash newest firmware first. pfSense uses MPD5 as a PPP daemon so these settings are only good for *BSD

    
    default:
     set log local Phase Chat LCP IPCP CCP tun command
     set device /dev/cuaU0.3
     set timeout 180
    
    att:
     set speed 921600
     set timeout 0
     set dial "ABORT BUSY TIMEOUT 2 \
            \"\" \
            AT OK-AT-OK \
            AT+CFUN=1 OK-AT-OK \
            AT+CMEE=2 OK-AT-OK \
            AT+CSQ OK \
            AT+CGDCONT=1,\\\"IP\\\",\\\"broadband\\\" OK \
            AT+CGACT? OK-AT-OK \
            AT+CGATT? OK \
            AT+CGCLASS? OK \
            AT+COPS? OK \
            ATD*99***1# CONNECT"
     enable dns
     resolv writable
     set dns 208.67.220.220 208.67.222.222	# openDNS
     set ifaddr 10.0.0.1/0 10.0.0.2/0 255.255.255.255 0.0.0.0
     add default HISADDR
    
    

    To dial connection i enter this at command prompt:
    ppp -ddial att

    Due to "local" turned on in the ppp.conf you can see the modems interaction with the AT commands. After dialing it returns -Connected-.

    Then i do a startx and browse away…



  • I finally got the SIM adapter for the windows machine, and Sierra Watcher is reporting "incorrect SIM" which apparently means that the card is carrier locked.  I bought it "new" and "unlocked" from a vendor on Amazon; I've requested the MEP unlock code from them and will return it and buy a new one from a more reputable vendor if no code is forthcoming (it's what I get for trying to save $15).

    On the windows machine, the AT commands you suggested all returned valid data; the only item that was different was that I had the 9200 version firmware instead of 9300.  I actually had flashed new firmware as your previous post suggested, but the link I used was:  http://source.sierrawireless.com/resources/#tags=MC7700|Firmwares+%26+drivers which doesn't show anything newer than 9200.

    That said, the AT!UDINFO? returned data.

    Thank you so much for diving into this; I apologize I hadn't done the legwork to make sure it worked with their software first.

    One more thing:  do you happen to know the difference between an APN of "broadband" and one of "pta"?  My phone lists both, but pta is selected; the label on pta is "ATT LTE".



  • That SW9300 ref was a typo i decided to keep to see if you would catch it!!! Good Catch. Mine is from 12-2014 date.

    The APN differences seem to be speed. Test yours and see. They seem lenient on devices but i believe that it is the proper APN for data card devices.

    So you think the device is locked?? I am more questioning your SIM card validity.

    I have never seen a locked MC7700, they were first in breed for LTE and uptake was low. Very few notebooks used them. Mostly Lenovo/IBM and embedded..Panasonic toughbooks optional too.

    I know of no carrier that offered the MC7700 in a device, let alone locked. Chinese sell them as unlocked as they have no idea.

    Edit: Rereading you post it is the SIM. I don't think you can use a phone SIM interchangeably with data devices. They are lenient on data device to data device transfer, but not from phone to data device swapage. Just my .02 cents.ymmv..



  • Quick and dirty way to check:
    Head to Walmart and get Straight Talk <tablet kit="">with sim and 1 gig data card. 25 bucks…LTE may be spottier than ATT but it works.. That or query att about data sim.
    Comes with mini and micro sims for ATT and Tmobile.</tablet>



  • I took your advice and got a StraightTalk data SIM from Walmart as I figured $25 to get to the bottom of this would be well worth it.

    It reports "Incorrect SIM" in the watcher as well.  So at this point, I think I have to assume the card itself is locked/problematic.



  • I have bought around a dozen of these modules off ebay and have not found a locked one yet. That is really strange..I was unaware there were locked versions…So you think it is carrier locked? I wonder what carrier. They are only a GSM module so in the US that is ATT or Tmobile, Right? Did you try the Tmobile SIM as well? You can swap cards activation on the StraightTalk site..



  • So I found some more AT commands that would tell me if it's locked:  AT!CUSTOM?.

    It was set to "Japan" as the region, but that's not supposed to do anything serious, and it's actually not MEP locked.  It just doesn't see the SIM at all; anything that involves accessing the SIM returns "ERROR".

    I'm sending it back for a replacement.  When I get the new one in a couple of weeks I'll try all this again.

    Thank you!



  • I am sorry you are having such problems..I was wondering in my head if the adapter SIM slot might be bad…

    Here is a link for recalibration procedures for the modem.

    https://forum.sierrawireless.com//viewtopic.php?f=117&t=8702



  • Well since you have the Straighttalk SIM kit have you tried using them in the APU to rule out bad sim socket on your usb adapter? Have you isolated the problem? What is MEB lock? I am unfamiliar with that term. Like I said earlier, I bought over a dozen modules off ebay and none were locked… What are the first 4 digits of your IMEI# ? Mine were all 0126 except one.



  • I thought this was only for the USB devices, but who knows. AC340U comes to mind(ATT-Beam)

    http://kb.netgear.com/app/answers/detail/a_id/22903/~/why-is-my-netgear-aircard-modem-locked%3F