EM20-G "No modem present"

[scott83]

I finally got my Verizon SIM. I have the Quectel EM20-G modem mounted in a USB3.0 To NGFF M.2 Key B Adapter Enclosure With SIM Card Slot. I only have two of the MHF4 pigtails connected at the moment. I have it currently plugged into a Linksys WRT3200ACM running the latest (as of yesterday) Goldenorb firmware. The EM20-G just has whatever firmware it came with from the factory (and my understanding is that with the current version of Goldenorb, this no longer needs to be downgraded).

When I go to Modem --> Miscellaneous, under Current Modem it is listed as "No Modem Present." Modem Debug Information just lists this a bunch: "Sat Jul 18 12:27:28 2020 : /dev/ttyUSB Can't open device /dev/ttyUSB."

In the Device Information section of Debug Information, I do see EM20-G listed as one of the devices:
" P: Vendor=2c7c ProdID=0620 Rev= 4.09
S: Manufacturer=Quectel
S: Product=EM20-G"

Any suggestions?

Thanks!

Scott

[LoveMeSomeCALTE]

Is there a syslog or kernel entry that loads the device driver and shows /dev/ttyUSB* being mapped?

[scott83]

I have since got the two other MHF4 connectors hooked up and lo and behold, it recognizes the modem!

Here are the logs:

Code: Select all

System Log:
Sat Jul 18 12:40:25 2020 user.notice usb-modeswitch: Found Modem1
Sat Jul 18 12:40:25 2020 user.notice usb-modeswitch: Connecting a QMI Modem
Sat Jul 18 12:40:25 2020 user.notice Create Connection: Start QMI Connection
Sat Jul 18 12:40:30 2020 user.notice Create Connection: QMI Comm Port : /dev/ttyUSB2
Sat Jul 18 12:40:30 2020 user.notice Create Connection: WDA-GET-DATA-FORMAT is "raw-ip"
Sat Jul 18 12:42:29 2020 user.notice Create Connection: Quectel Unsolicited Responses Disabled

Kernel Log:
[   16.818205] usbserial: USB Serial support registered for GSM modem (1-port)
[   16.825454] option 3-1:1.1: GSM modem (1-port) converter detected
[   16.831704] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB0
[   16.838633] option 3-1:1.2: GSM modem (1-port) converter detected
[   16.844874] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB1
[   16.851813] option 3-1:1.3: GSM modem (1-port) converter detected
[   16.858036] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB2
[   16.866674] usbcore: registered new interface driver qcserial
[   16.872526] usbserial: USB Serial support registered for Qualcomm USB modem

However, it seemed to only recognize it when I turned the router and modem on simultaneously (modem enclosure plugged into USB3 port on router). If I unplug it and plug it back in, it is no longer recognized. This only works without the SIM card inserted. If I insert it, connect it to the router, and reboot the router, it says "No Modem Present." Initially, that is, without doing anything the modem did become recognized during the time that it took me to type this up.

Here are the log files in that situation:

Code: Select all

System Log:

Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.685780] usbserial: USB Serial support registered for GSM modem (1-port)
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.692985] option 3-1:1.1: GSM modem (1-port) converter detected
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.699254] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB0
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.706216] option 3-1:1.2: GSM modem (1-port) converter detected
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.712478] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB1
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.719417] option 3-1:1.3: GSM modem (1-port) converter detected
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.725667] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB2
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.734160] usbcore: registered new interface driver qcserial
Tue Jul 21 16:43:18 2020 kern.info kernel: [   16.739995] usbserial: USB Serial support registered for Qualcomm USB modem


Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: Add : 3-1: Manufacturer=Quectel Product=EM20-G Serial=74cd8c74 2c7c 0620
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: * Start of Modem Detection and Connection Information
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: * Product=EM20-G 2c7c 0620
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: * This device does not have a switch data file
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: * Product=EM20-G 2c7c 0620
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:32 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:32 2020 daemon.info dnsmasq-dhcp[5331]: DHCPREQUEST(br-lan) 192.168.1.173 a4:5e:60:de:dc:97
Tue Jul 21 16:43:32 2020 daemon.info dnsmasq-dhcp[5331]: DHCPACK(br-lan) 192.168.1.173 a4:5e:60:de:dc:97 Scotts-MBP
Tue Jul 21 16:43:36 2020 daemon.err uhttpd[3692]: luci: accepted login on /admin/status/dmesg for root from 192.168.1.173
Tue Jul 21 16:43:36 2020 daemon.info hostapd: wlan0: STA a4:5e:60:de:dc:97 IEEE 802.11: authenticated
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: * Switched to : 2c7c:0620
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:42 2020 user.notice Log Print : Driver Name : 2 option
Tue Jul 21 16:43:42 2020 user.notice Log Print : Driver Name : 3 option
Tue Jul 21 16:43:42 2020 user.notice Log Print : Driver Name : 4 option
Tue Jul 21 16:43:42 2020 user.notice Log Print : Driver Name : 5 qmi_wwan
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: * ProtoFind returns : 2
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: *****************************************************************
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: Found Modem1
Tue Jul 21 16:43:42 2020 user.notice usb-modeswitch: Connecting a QMI Modem
Tue Jul 21 16:43:42 2020 user.notice Create Connection: Start QMI Connection
Tue Jul 21 16:43:47 2020 user.notice Create Connection: QMI Comm Port : /dev/ttyUSB2
Tue Jul 21 16:43:50 2020 user.notice Create Connection: WDA-GET-DATA-FORMAT is "raw-ip"
Tue Jul 21 16:45:49 2020 user.notice Create Connection: Quectel Unsolicited Responses Disabled

Kernel Log:
  16.685780] usbserial: USB Serial support registered for GSM modem (1-port)
[   16.692985] option 3-1:1.1: GSM modem (1-port) converter detected
[   16.699254] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB0
[   16.706216] option 3-1:1.2: GSM modem (1-port) converter detected
[   16.712478] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB1
[   16.719417] option 3-1:1.3: GSM modem (1-port) converter detected
[   16.725667] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB2
[   16.734160] usbcore: registered new interface driver qcserial
[   16.739995] usbserial: USB Serial support registered for Qualcomm USB modem

It now says "Provider: Connecting" under Signal/Cell Information. The SIM is inserted and I have the Verizon APN (well, the Visible one, which the provider says to use: VSBLINTERNET).

Is there some command I need to send it now to help it connect?

Thanks for the help!

[scott83]

But, I cannot consistently get it to be recognized. Just a few minutes ago it was and then without touching any of the hardware, it says "No Modem Present," but still gives a Modem ID. Very weird.

[WompWomp]

I had something similar whilst firing up the EM20-G in an M.2 enclosure for the first time today. Without a SIM the modem was recognized but after putting one in I started seeing "No Modem Present" errors.

I think it was happening because of power constraints - I had it running off of USB power from a Raspberry Pi. I gave the M.2 enclosure its own power supply and that seems to have resolved it.

[scott83]

Very interesting. I would think the USB3 port on my router would supply enough, but maybe not. I’ll try out a secondary power supply as soon as I find a plug that fits it.

Thanks for the suggestions!

[Didneywhorl]

Very interesting. I would think the USB3 port on my router would supply enough, but maybe not. I’ll try out a secondary power supply as soon as I find a plug that fits it.

Thanks for the suggestions!

The router specs usually dont state the output power, sometimes they do. The EM20G is a monster power hog, especially when going full 3xCA or higher.

A good indicator of low power is the modem dropping out at seeming random

[scott83]

Thanks for the suggestions about the power. It seems to recognize the modem better now...at least partially. This is what I get without a SIM card installed.

Screen Shot 2020-07-23 at 7.57.35 PM.png

However, when I go to Miscellaneous Modem Features, I get this:

Screen Shot 2020-07-23 at 7.48.09 PM.png

Sorry, I'm so new. I tried searching but can't find anything that matches the specific problem I'm having. I can't get this to say "Modem Connected" and can't send any AT commands.

Thanks!

[MattB29]

Without a sim card (or one that does not fit right) you are not going to show connected.

[scott83]

Without a sim card (or one that does not fit right) you are not going to show connected.

I have a SIM card installed now. It seemed to fit okay. I felt it click into place. It still shows "Modem Present/Not Connected."

Any suggestions? Here are how things look now:

Screen Shot 2020-07-24 at 7.09.50 PM.png

Screen Shot 2020-07-24 at 7.11.14 PM.png

Screen Shot 2020-07-24 at 7.11.25 PM.png

[MattB29]

Well at least your modem is detected and is attempting to connect.

I assume you have the APN set. You should be able to use AT command under the Modem>Miscellaneous tab to get status (enter command: at!gstatus?). There is a Thread on the Forum here for troubleshooting connection issues. Might want to go through it.

[Didneywhorl]

Set your TTL for ipv4 and ipv6 to 117

Under Network-->Firewall-->Custom Firewall Rules

Paste:

#start TTL rules Change all the values of "65" to any you choose, maybe 64, or 117 seems popular for Verizon
iptables -t mangle -I POSTROUTING -o wwan0 -j TTL --ttl-set 65
iptables -t mangle -I PREROUTING -i wwan0 -j TTL --ttl-set 65

#Start IPV6 TTL (hl) rules … usually onlyneeded for T-Mobile and sometimes Verizon, not recommended for ATT
ip6tables -t mangle -I POSTROUTING -o wwan0 -j HL --hl-set 65
ip6tables -t mangle -I PREROUTING -i wwan0 -j HL --hl-set 65
#end TTL rules

Also make sure your time settings are synced and time zone set correctly

Menu: System-->System

[scott83]

I’ve changed the TTL and made sure time settings are synced. It still tells me Modem Present/Not Connected. AT commands don’t do anything. It just says “Waiting for a Response.” This happens either with or without a SIM card inserted. Even if the SIM is bad, the modem should still be able to respond to commands, right?

I can SSH in as well. Any suggestions? I found the troubleshooting connections for Sierra modems but not much on the EM20-G.

[Yipzy]

I’ve changed the TTL and made sure time settings are synced. It still tells me Modem Present/Not Connected. AT commands don’t do anything. It just says “Waiting for a Response.” This happens either with or without a SIM card inserted. Even if the SIM is bad, the modem should still be able to respond to commands, right?

I can SSH in as well. Any suggestions? I found the troubleshooting connections for Sierra modems but not much on the EM20-G.

Try

Code: Select all

AT+QCFG="usbnet"

if you get a response then

Code: Select all

AT+QCFG="usbnet",2

for MBIM mode then restart modem.

Try

Code: Select all

picocom -b 115200 /dev/ttyUSB2

in SSH if you can't it issue AT commands through interface.

If modem is responding to AT commands follow my post here afterward https://wirelessjoint.com/viewtopic.php?p=10569#p10327

[scott83]

Thanks, Yipzy. I tried issuing that AT command and got no response. When I SSH'd in I got this message:

Code: Select all

root@ROOter:~# picocom -b 115200 /dev/ttyUSB2
picocom v1.7

port is        : /dev/ttyUSB2
flowcontrol    : none
baudrate is    : 115200
parity is      : none
databits are   : 8
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,

Terminal ready

It then seems to not respond to any of my typing and just sits there.

[Yipzy]

Thanks, Yipzy. I tried issuing that AT command and got no response. When I SSH'd in I got this message:

Code: Select all

root@ROOter:~# picocom -b 115200 /dev/ttyUSB2
picocom v1.7

port is        : /dev/ttyUSB2
flowcontrol    : none
baudrate is    : 115200
parity is      : none
databits are   : 8
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,

Terminal ready

It then seems to not respond to any of my typing and just sits there.

try

Code: Select all

dmesg | grep tty

to see which ttyUSB it is available for the modem then try picocom command with other /dev/ttyUSBx also try without the baud rate

Code: Select all

picocom /dev/ttyUSBx

replace x with a number

picocom help page https://manpages.debian.org/testing/pic ... .1.en.html

If you are still having problem getting the modem to respond with AT commands, I suggest you post the logs to the guys who build GoldenOrb/ROOter over https://forums.whirlpool.net.au/thread/2689577 for more expert advice. I don't have access to GoldenOrb/ROOter router anymore to test or go along so I'm going by what I know and remember. But do follow my post after you got it to respond to AT commands. It should get your Quectel modem to connect to Verizon.