MC7700 Connect Error


#1

I’m using Debian Linux 7.0. I have a MC7700 card and a AT&T SIM card on the dev board connected over USB, with both antennas connected. I connected to my MC7700 over serial and followed the instructions given on the “Can I use a Sierra Wireless modem with Linux” page. I want to connect to an AT&T data plan, so I did the following:

at+cgdcont?
+CGDCONT: 1,“IP”,“Broadband”,“0.0.0.0”,0,0
+CGDCONT: 2,“IP”,“wap.cingular”,“0.0.0.0”,0,0
at+cfun=1
OK
at!scact=1,1
+CME Error: no network service
[ 7265.111629] sierra_new 1-1:1.7: wwan0: Link type unsupported: 0xff
[ 7265.111629] sierra_new 1-1:1.7: wwan0: Invalid LSI

The last two lines are output from dmesg, not serial data from the card. I have a recent version of both the sierra and sierra_net drivers (1.7.16 and 2.0 respectively), so I don’t know why I would get this error. What circumstances cause this error? What can I do to avoid this error?


#2

Hi,

Can you share the dmesg log showing the USB enumeration of MC7700?
Also, please try to send AT!GSTATUS? before AT!SCACT and share the response.

Thx.
L


#3

Log from dmesg:

USB Serial support registered for Sierra USB modem
sierra 4-1.7:1.0: Sierra USB modem converter detected
usb 4-1.7: Sierra USB modem converter now attached to ttyUSB0
sierra 4-1.7:1.1: Sierra USB modem converter detected
usb 4-1.7: Sierra USB modem converter now attached to ttyUSB1
sierra 4-1.7:1.2: Sierra USB modem converter detected
usb 4-1.7: Sierra USB modem converter now attached to ttyUSB2
sierra 4-1.7:1.3: Sierra USB modem converter detected
usb 4-1.7: Sierra USB modem converter now attached to ttyUSB3
sierra 4-1.7:1.4: Sierra USB modem converter detected
usb 4-1.7: Sierra USB modem converter now attached to ttyUSB4
usbcore: registered new interface driver sierra
sierra: v.1.7.16:USB Driver for Sierra Wireless USB modems

Here’s at!gstatus? before at+cfun=1:

Current Time: 277
Temperature: 23
Bootup Time: 1
Mode: LOW POWER MODE
System mode: Unknown
PS State: Not attached
GMM (PS) state: DEREGISTERED
NO SERVICE
MM (CS) state: IDLE
NO SERVICE

Here’s at!gstatus? after at+cfun=1:

Current Time: 367
Temperature: 23
Bootup Time: 1
Mode: ONLINE
System mode: LTE
PS State: Not attached
LTE band: B4
LTE bw: 10 Mhz
LTE Rx chan: 2115
LTE Tx chan: 65535
EMM (PS) state: DEREGISTERED
Attach Needed
RSSI (dBm): 0
Tx Power: 0
RSRP (dBm): 0
TAC: 0000 (0)
RSRQ (dB): 0
Cell ID: 00000000 (0)
SINR (dB): -20.0

After a while, here’s the at!gstatus?:

Current Time: 525
Temperature: 25
Bootup Time: 1
Mode: ONLINE
System mode: GSM
PS State: Not attached
GSM band: Unknown
GSM channel: 65535
GMM (PS) state: DEREGISTERED
NO SERVICE
MM (CS) state: IDLE
NO SERVICE

Serving Cell: 0 (No band )
RX level (dBm): 0.0
LAC: 0000 (0)
GPRS State: GPRS IDLE
Cell ID: 00000000 (0)

Let me know if you need any more information.


#4

From !GSTATUS, it shown that no service (not registered with network) thus AT!SCACT fail.
Could you please check the antenna connection and if network coverage available at your test location?

Also, can you please check:
AT!ENTERCND="***" (please enter the correct password)
AT!UDPID?
AT!UDUSBCOMP?

Thanks.


#5

I’ve been trying some things. When I switch to only band 09 (LTE), rather than all bands, and then do AT+CFUN=1 then AT!SCACT=1,1 the card freezes.

I tried all three of the commands you asked me to run, and they all give an error. Is there a default password for AT!ENTERCND for these cards? Are the two following commands AT!UDPID? and AT!UDUSBCOMP? dependent on entering the correct password for AT!ENTERCND?


#6

Both !UDPID and !UDUSBCOMP works only if a correct password was entered via !ENTERCND.
The reason I ask for their response is that !SCACT rely on NDIS (sierra_net) driver, but I didn’t see it in your USB enumerate log.

To get the password, please check with your distributor.

For the freeze, try check !GSTATUS before you send !SCACT, this is to check MC7700 status.
But again, please make sure antenna is connected during your test.
Thx.


#7

Alright, here’s the output of those commands.

AT!UDPID?

!UDPID: 68A3

OK

AT!UDUSBCOMP?

!UDUSBCOMP: 3

OK

The antenna is definitely connected securely.


#8

I see what you meant by connecting the antenna now. After doing that properly, I was able to get the 4G connected. Thanks for your help.