MC7455 USB interface for PPP connection

jyijyi · July 4, 2020, 11:45am

Seems only one AT port can be used.

you can use rmnet where you can use qmi sdk to get the rssi.

v.tadevosyan · July 4, 2020, 11:53am

Thank you!
About CMUX: how can I activate CMUX on AT port?

jyijyi · July 4, 2020, 12:33pm

Please see the +cmux command in user guide

v.tadevosyan · July 4, 2020, 12:56pm

I have already read command reference. It says +CMUX is supported when MUX
mode configured on USB interface. So, my question is how to enable/configure on USB interface? Should I use !USBCOMP command to do it or it is something that should be done on the system?

With Regards,
Vahe

jyijyi · July 4, 2020, 1:46pm

I think you can directly try on usb AT port first.

v.tadevosyan · July 4, 2020, 5:20pm

Dear jyijyi,

Thank you for recommendation! The point is that AT+CNUM command returns ERROR. The command reference document of MC7455 states that +CNUM command is supported only when the MUX mode is enabled on USB interface. Should the system be changed to enable MUX mode or it should be done by another AT command?

jyijyi · July 4, 2020, 11:34pm

Just have a try here, you are right, the mux command cannot be entered.
Then probably you need to use QMI SDK to get the RSSI.

v.tadevosyan · July 6, 2020, 8:36am

Ok jyijyi, thank you very much!

v.tadevosyan · July 6, 2020, 9:10am

Hi jyijyi,

During my investigations to find out the right usbcomp of MC7455 for me I eventually lost my AT command port after changing the USBPID to 9068 and setting usbcomp=1,3,50D. So, now my MC7455 module runs in RNDIS mode and there is no AT port to switch back to Generic mode (usbcomp=1,1,50D). Is there a method to reset the settings to factory default? I have an evaluation board to connect MC7455 to PC.

With Regards,
Vahe

jyijyi · July 6, 2020, 9:39am

what port did you see in linux platform?
Not sure if you can use /dev/cdc-wdm port and switch back like this link:

mlw · July 6, 2020, 10:42am

@v.tadevosyan

Hopefully I don’t throw a spanner in the works but you can use the RMNet interface using ~AT commands just as you were able to use DirectIP with the MC7710. To do this have a read of this document 1aec569af75a1ab07c66bf85086071fc482f614b.docx (347.1 KB) a lot of ourEM/MC74 customer use the unit this way, you do really need to use the GobiSerial and Net drivers.

PPP was deprecated by Qualcomm quite sometime ago although it still works, it is not really recommended because there are a lot of limitations (not least the deprecated bit).

Regards

Matt

v.tadevosyan · July 6, 2020, 11:02am

Thank you! It was very useful information! I will give it a try.

v.tadevosyan · July 6, 2020, 11:05am

Hi jyijyi,

I connected MC7455 (with lost AT command port, it is in RNDIS mode) to my PC (running Ubuntu 18.04) and found out the following in dmesg:

[ 8455.619141] usb 1-1: new high-speed USB device number 10 using xhci_hcd
[ 8455.769743] usb 1-1: New USB device found, idVendor=1199, idProduct=9068
[ 8455.769748] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 8455.769752] usb 1-1: Product: MC7455
[ 8455.769755] usb 1-1: Manufacturer: Sierra Wireless, Incorporated
[ 8455.769758] usb 1-1: SerialNumber: LQ82639012011025
[ 8455.775049] rndis_host 1-1:1.0 usb0: register ‘rndis_host’ at usb-0000:00:14.0-1, RNDIS device, aa:e7:96:36:f3:b1
[ 8455.793267] rndis_host 1-1:1.0 enp0s20f0u1: renamed from usb0
[ 8455.822862] IPv6: ADDRCONF(NETDEV_UP): enp0s20f0u1: link is not ready

Is there a chance to change it to generic mode?

jyijyi · July 6, 2020, 11:16am

You might try to use what mlw recommemded so that you can send AT command to change it back to generic

v.tadevosyan · July 6, 2020, 11:39am

Dear jyijyi,

mlw’s recommendation is related to using RMNET interface as other wired network interface after module is connected to network using AT commands. I hope this will be useful for us. I will give it a try.
Before that I need to restore my usbcomp to Generic mode. It is now in RNDIS mode and I lost AT port. My questions is: is there a way to change back the USBCOMP to generic mode if my module is in RNDIS mode?

dl5162 · July 6, 2020, 11:39am

Please note the age of that info. It is currently 5 years old, and has been outdated for some time. And it has always been unsupported by Sierra Wireless for obvious reasons.

dl5162 · July 6, 2020, 11:47am

please post the output of

lsusb -vd 1199:9068

and/or try

modprobe option
echo  "1199 9068"  > /sys/bus/usb-serial/drivers/option1/new_id

and see if there is any /dev/ttyUSBx devices accepting AT commands after that. If there is, then use the documented and supported commands to switch back to a supported mode.

v.tadevosyan · July 6, 2020, 12:14pm

Hi dl5162,

The following is answer to lsusb -vd 1199:9068

lsusb -vd 1199:9068

Bus 001 Device 014: ID 1199:9068 Sierra Wireless, Inc.
Couldn’t open device, some information will be missing
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x1199 Sierra Wireless, Inc.
idProduct 0x9068
bcdDevice 0.06
iManufacturer 1
iProduct 2
iSerial 3
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 147
bNumInterfaces 4
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 3
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 0
iInterface 0
** UNRECOGNIZED: 05 24 00 10 01
** UNRECOGNIZED: 05 24 01 00 00
** UNRECOGNIZED: 04 24 02 02
** UNRECOGNIZED: 05 24 06 00 00
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x000a 1x 10 bytes
bInterval 9
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 2
bFunctionClass 224 Wireless
bFunctionSubClass 1 Radio Frequency
bFunctionProtocol 3 RNDIS
iFunction 7
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 3 RNDIS
iInterface 5
** UNRECOGNIZED: 05 24 00 10 01
** UNRECOGNIZED: 05 24 01 00 01
** UNRECOGNIZED: 04 24 02 00
** UNRECOGNIZED: 05 24 06 00 01
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 9
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 6
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x84 EP 4 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0

Looking forward to any recommendation to restore my MC7455’s AT port.
Thanks

v.tadevosyan · July 6, 2020, 12:40pm

Dear @dl5162 ,

I tried with

modprobe option
echo  "1199 9068"  > /sys/bus/usb-serial/drivers/option1/new_id

After that 2 serial ports were created and the /dev/ttyUSB1 was my AT port. I configured back to generic mode my MC7455 successfully!!!
Thank you very much for your help!
With Regards,
Vahe

v.tadevosyan · July 6, 2020, 12:46pm

Dear @mlw,

After restoring my unit back to generic mode of USBCOMP, I tried your suggestion to connect to network using AT command and then used eth interface to access internet successfully. Thank you very much!
It was done on my Linux machine. The only point I need now to port GobiNet driver to my old system.

Thanks again,
Vahe