no /dev/ttyUSB0 - how can I add this?

English Hardware
#1

Leap 15.2 running on a 10 yr old Dell tower.
I want to connect to the serial console port of a router using putty (I need to grab a session log).

This computer does not have a serial /dev/ttyUSB* nor does it have a 9 pin rs232 port.

This is what dmsg -w has to say when I connect the cable:

  223.248047] usb 2-2: new full-speed USB device number 3 using xhci_hcd
  223.376089] usb 2-2: device descriptor read/64, error -71
  223.612068] usb 2-2: device descriptor read/64, error -71
  223.848036] usb 2-2: new full-speed USB device number 4 using xhci_hcd
  223.976074] usb 2-2: device descriptor read/64, error -71
  224.212078] usb 2-2: device descriptor read/64, error -71
  224.320103] usb usb2-port2: attempt power cycle
  224.972055] usb 2-2: new full-speed USB device number 5 using xhci_hcd
  224.972222] usb 2-2: Device not responding to setup address.
  225.180212] usb 2-2: Device not responding to setup address.
  225.388074] usb 2-2: device not accepting address 5, error -71

And this is the output of lsusb:

Bus 003 Device 003: ID 058f:6362 Alcor Micro Corp. Flash Card Reader/Writer
Bus 003 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0cf3:e004 Qualcomm Atheros Communications 
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 002 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Perhaps this computer is not capable of a serial connection via usb but if it is something to do with the OS I’d like to see if I can get somewhere with this. One thing I have done is boot computer w/ cable attached. I’ll do this after posting on the off chance that the kernel will recognize it.

I did find something online about MAKEDEV but I don’t want to go blindly messing around without more info.

#2

Hi
You need a USB to serial convertor (I use a Sabrent USB 2.0 to Serial (9-Pin) DB-9 RS-232 Converter Cable, Prolific Chipset), you should see something like;


Bus 002 Device 005: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

ls -la /dev/ttyUSB0

crw-rw---- 1 root dialout 188, 0 Apr 23 20:14 /dev/ttyUSB0

Add you user to the dialout group as well…

#3

As Malcolm mentioned already a USB-serial adapter is required. The chipset matters, as that will determine if the kernel supports it out of the box. I use a PL2303 device which works nicely for the few times I need to access network equipment via PuTTY.

#4

re: chipset. Thanks, at least now I can stop wasting my energy looking for a solution on that computer. And thanks for mentioning the device that I need to make it work.

#5

OP here with more questions on this topic.

To amplify my phrase “serial console port” what I need is to connect via usb to a router which uses a usb mini-b port.

The solution Malcolm mentioned, a usb serial adapter, is usb->db9. Sorry I failed to use the correct terminology for my needs.

On an older computer I no longer have and using a different distro, I successfully used cu /dev/ttyUSB0 so I don’t know why that is not in my version of Leap.

Furthermore, the notes I have from manuf is that it may need a Prolific pl2303gc driver. There is a pl2303.ko on my system but I cannot load it with insmod or probemod. I hoped if I could load that driver I could make some progress.
I did try putty and could not get it configure the port, using various ttySx.
I’m thinking it could be the lack of ttyUSB0 and/or the pl2303.ko is not loaded (I checked w/ lsmod).

Are there any other things I can try given the additional info here?

#6

I assume that you have the requisite cable? What brand of router?

I note that some Cisco routers include such ports for console access. How does the USB device appear when connected this way?

lsusb

usb-devices

If it is seen as a (serial) console port, I would expect a /dev/ttyUSB* device node to be present assuming there is driver support for it. Check with

ls /dev/ttyUSB*

Furthermore, the notes I have from manuf is that it may need a Prolific pl2303gc driver. There is a pl2303.ko on my system but I cannot load it with insmod or probemod. I hoped if I could load that driver I could make some progress.

Ordinarily there should be no need to load the driver manually. If Linux recognises the device, then the driver will be loaded automatically.

I note from reading…
https://prolificusa.com/product/pl2303gc-usb-full-uart-bridge-controller-gpio/
…that Kernel 5.5+ already includes built-in drivers for the PL2303G chipset.

Connect to the router console port and examine the kernel output…

dmesg | tail
#7

Hi
No, not necessarily I do have USB to DB9, but also same device but USB to RS232 TTL Converter 4 Pin for the RPi’s and other devices (eg gps).

#8

Of course. It is a Netgate router/firewall appliance.

I note that some Cisco routers include such ports for console access. How does the USB device appear when connected this way?

On my circa 2003 Pentium 4 laptop running freebsd it prints to screen “<Prolific Technology Inc. USB-Serial Controller>”
The documentation refers to it as:
Prolific USB to Full UART Bridge Controller with GPIO
Chip Number PL2303GC

lsusb
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 002: ID 046d:c063 Logitech, Inc. DELL Laser Mouse
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 002: ID 0483:2016 STMicroelectronics Fingerprint Reader
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Thank you for mentioning this command, I was unaware of it. Below output shows the device detected at the last entry for Bus 5.
There is no screen output when connecting the cable.

usb-devices
T:  Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=480 MxCh= 4
D:  Ver= 2.00 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0002 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default ehci_hcd
S:  Product=EHCI Host Controller
S:  SerialNumber=0000:00:1a.7
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

T:  Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=480 MxCh= 6
D:  Ver= 2.00 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0002 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default ehci_hcd
S:  Product=EHCI Host Controller
S:  SerialNumber=0000:00:1d.7
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

T:  Bus=03 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0001 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default uhci_hcd
S:  Product=UHCI Host Controller
S:  SerialNumber=0000:00:1a.0
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

T:  Bus=03 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#=  2 Spd=12  MxCh= 0
D:  Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=0483 ProdID=2016 Rev=00.01
S:  Manufacturer=STMicroelectronics
S:  Product=Biometric Coprocessor
C:  #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA
I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)

T:  Bus=04 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0001 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default uhci_hcd
S:  Product=UHCI Host Controller
S:  SerialNumber=0000:00:1a.1
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

T:  Bus=05 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0001 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default uhci_hcd
S:  Product=UHCI Host Controller
S:  SerialNumber=0000:00:1d.0
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

T:  Bus=05 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=1.5 MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=046d ProdID=c063 Rev=57.00
S:  Manufacturer=DELL
S:  Product=DELL USB Laser Mouse
C:  #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=98mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=02 Driver=usbhid

T:  Bus=05 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#=  3 Spd=12  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=067b ProdID=23a3 Rev=01.05
S:  Manufacturer=Prolific Technology Inc. 
S:  Product=USB-Serial Controller 
S:  SerialNumber=BUAMj19B616
C:  #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA
I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)

T:  Bus=06 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0001 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default uhci_hcd
S:  Product=UHCI Host Controller
S:  SerialNumber=0000:00:1d.1
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

T:  Bus=07 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1d6b ProdID=0001 Rev=05.03
S:  Manufacturer=Linux 5.3.18-lp152.75-default uhci_hcd
S:  Product=UHCI Host Controller
S:  SerialNumber=0000:00:1d.2
C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub

If it is seen as a (serial) console port, I would expect a /dev/ttyUSB* device node to be present assuming there is driver support for it.

The driver is not in the kernel, but one exists in the file structure and I am unable to insmod or modprobe that driver, pl2303.ko.

ls /dev/ttyUSB*
ls: cannot access '/dev/ttyUSB*': No such file or directory

I note from reading…
https://prolificusa.com/product/pl2303gc-usb-full-uart-bridge-controller-gpio/
…that Kernel 5.5+ already includes built-in drivers for the PL2303G chipset.

My Leap15.2 kernel is reported as 5.3.18 not 5.5

Connect to the router console port and examine the kernel output…

dmesg | tail
  709.174244] BTRFS info (device sda5): qgroup scan completed (inconsistency flag cleared)
 1434.839253] usb 5-2: new full-speed USB device number 3 using uhci_hcd
 1435.038231] usb 5-2: New USB device found, idVendor=067b, idProduct=23a3, bcdDevice= 1.05
 1435.038238] usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
 1435.038243] usb 5-2: Product: USB-Serial Controller 
 1435.038247] usb 5-2: Manufacturer: Prolific Technology Inc. 
 1435.038251] usb 5-2: SerialNumber: BUAMj19B616
 1448.187420] usb 5-2: USB disconnect, device number 3

Also, my memory failed me in my prior post. I said ttyUSB0 but that was incorrect. The command I was using on my old laptop running freebsd was

sudo cu -l /dev/cuaU0 -s 115200

There is no cuaU0 on my Leap.

#9

Hi
There is also ttySn and ttyAMAn;

My RPi3 gps/chrony time server;


ls /dev/ttyA*

/dev/ttyAMA0

cat /etc/sysconfig/gpsd | grep OPTIONS
GPSD_OPTIONS="-G -n -b /dev/ttyAMA0 /dev/pps0"



 lsusb | grep Prolific

Bus 002 Device 009: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port <== USB -> TTL
Bus 002 Device 010: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port <== USB -> RS232

T:  Bus=02 Lev=01 Prnt=01 Port=08 Cnt=07 Dev#=  9 Spd=12  MxCh= 0
D:  Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=067b ProdID=2303 Rev=03.00
S:  Manufacturer=Prolific Technology Inc.
S:  Product=USB-Serial Controller
C:  #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA
I:  If#=0x0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=pl2303

T:  Bus=02 Lev=01 Prnt=01 Port=09 Cnt=01 Dev#= 10 Spd=12  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=067b ProdID=2303 Rev=03.00
S:  Manufacturer=Prolific Technology Inc.
S:  Product=USB-Serial Controller
C:  #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA
I:  If#=0x0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=pl2303

lsmod | grep pl2303

pl2303                 28672  0
usbserial              61440  1 pl2303
usbcore               323584  11 pl2303,usbserial,xhci_hcd,ehci_pci,usbnet,usbhid,usb_storage,ehci_hcd,xhci_pci,uas,ax88179_178a

ls /dev/ttyUS*

/dev/ttyUSB0  /dev/ttyUSB1
#10

I had a look around and this is what they say on connecting to the console.

That means you do not need an USB 2 Serial adapter, just plug in the cable into your Opensuse PC and:

If the device does not appear automatically, the CP210x driver module may need to be loaded manually, especially if the version of Linux being run is not recent. If the driver was provided with the Linux distribution, run modprobe cp210x as root or using sudo. If it had to be built manually, run insmod ./cp210x.ko assuming the module is in the current directory.

#11

Whether built as a module or otherwise, it is considered part of the kernel.

My Leap15.2 kernel is reported as 5.3.18 not 5.5

A more recent kernel, so support exists. :wink:

This provides a clue though…

dmesg | tail
  709.174244] BTRFS info (device sda5): qgroup scan completed (inconsistency flag cleared)
 1434.839253] usb 5-2: new full-speed USB device number 3 using uhci_hcd
 1435.038231] usb 5-2: New USB device found, idVendor=067b, idProduct=23a3, bcdDevice= 1.05
 1435.038238] usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
 1435.038243] usb 5-2: Product: USB-Serial Controller 
 1435.038247] usb 5-2: Manufacturer: Prolific Technology Inc. 
 1435.038251] usb 5-2: SerialNumber: BUAMj19B616
 1448.187420] usb 5-2: USB disconnect, device number 3

As you can see the device disconnects soon after appearing. This needs to be investigated further.

#12

I missed this reply. Yes, read the guide as per the link given.

#13

That info is not applicable to my situation.
The correct link is https://docs.netgate.com/pfsense/en/latest/solutions/sg-5100/connect-to-console.html

#14

Hi
One of these… USB to UART which is A.K.A USB to TTL… get an old USB mini cable and adapt to the TTL output connector…

#15

Hi
Looks like the chip is on the pfsense device… just have to compare the device id that pops up, I expect it should be supported in 15.2 kernel pl2303 kernel module…

#16

Would have been good if you had posted that earlier.

Did run read what is under the “Linux” tab?

#17

In this case I believe I pulled the usb after the output. I have had it plugged in now for several minutes and it has not disconnected.

Regarding various replies in the past few hours:

  1. I still need to know how, or if, I can load a driver.
  2. A reply indicated newer kernel. My kernel is via Leap15.2 repository updated regularly. Can I update to a newer kernel without a full install of a beta?

There is no output for:


lsmod | grep Prolific
lsmod | grep pl2303



# lsusb | grep Prolific
Bus 004 Device 003: ID 067b:23a3 Prolific Technology, Inc. 
#
#18

The chip is on the device. As I said, pl2303.ko exists in the kernel file tree but it is not loaded as determined by lsmod. I’ve tried to load it manually and it throws an error.
This is why I’m here asking questions. I posted a link to the manuf document, correcting the posted link by another user that points to a different device than the one I use.

Also, I note your signature shows you using Tumbleweed. I have not followed anything regarding that product, is it using the 5.5 kernel?
Will the upcoming leap15.3 use the 5.5 kernel? If so maybe I should wait for it’s release.

#19

Of course.

  1. It talks about ttyUSB0. That is the subject of this post. There is no ttyUSB0 on my Leap15.2
    I tried ttyS1, S2, & S3 with error “cannot configure port”

It seems to me, but I’m not exactly as knowledgable as many forum users, that I don’t have a Prolific driver installed.
My more recent comments are seeking to find out how to load this driver since it fails to load when I try various suggestions found online in other places.

What are you suggesting that I am not doing?

#20

Hi
The device is ok, do you see output from the following?


modinfo pl2303 | grep 23A3

{In Tumbleweed I see}
modinfo pl2303 | grep 23A3
alias:          usb:v067Bp23A3d*dc*dsc*dp*ic*isc*ip*in*

If you see output in above, then likely a udev rule issue… to see the device and load the driver.