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qherring

Member

Registered: 2023-05-05

Posts: 87

Troubleshooting USB Ethernet connection [SOLVED]

I have a USB-A to RJ45 adapter cable connected directly from my router's LAN port to laptop.  This isn't a dongle but rather a cable with two different end types.
I can get the USB cable device to show but I cannot properly set it to connect (I am using networkmanager):

lsusb --verbose

Bus 001 Device 045: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x0403 Future Technology Devices International, Ltd
  idProduct          0x6001 FT232 Serial (UART) IC
  bcdDevice            6.00
  iManufacturer           1 FTDI
  iProduct                2 FT232R USB UART
  iSerial                 3 A9XR9HTO
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0020
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower               90mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              2 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 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     0x0040  1x 64 bytes
        bInterval               0

ip link

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
    link/ether 58:1c:f8:34:cc:d1 brd ff:ff:ff:ff:ff:ff
17: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether 80:3f:5d:f7:af:30 brd ff:ff:ff:ff:ff:ff
    altname enp0s20f0u12u1u4

if I try to do:

ip link set eth0 up

it still shows as down connection.

ethtool enp0s20f0u12u1u4

Settings for eth0:
        Supported ports: [ TP    MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Half 1000baseT/Full
                                2500baseT/Full
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: 10Mb/s
        Duplex: Half
        Auto-negotiation: on
        Port: MII
        PHYAD: 32
        Transceiver: internal
netlink error: Operation not permitted
        Current message level: 0x00007fff (32767)
                               drv probe link timer ifdown ifup rx_err tx_err tx_queued intr tx_done rx_status pktdata hw wol
        Link detected: no

WiFi connections work fine, and I am able to connect via Ethernet through a docking station using a USB-C cable.  However, when I am mobile I dont bring the docking station but need Ethernet.

Last edited by qherring (2024-02-29 02:25:49)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,642

Re: Troubleshooting USB Ethernet connection [SOLVED]

As a sanity check, if you remove the cable, does the FTDI device in lsusb go missing?

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seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,030

Re: Troubleshooting USB Ethernet connection [SOLVED]

This isn't a dongle but rather a cable with two different end types

Same thing.

As long as it says "no carrier" this will not work. It means the NIC says "I don't believe there's a cable connecting me to anything else".
In what order do you plug the cables, first the rj45 or first the USB end? Does it matter? What is the rj45 end plugged into? What if you re-plug that?
Make sure it firmly snaps in on that end.
Do you get it to get you a carrier on other systems or against other peers?

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qherring

Member

Registered: 2023-05-05

Posts: 87

Re: Troubleshooting USB Ethernet connection [SOLVED]

As a sanity check, if you remove the cable, does the FTDI device in lsusb go missing?

Yeah

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,642

Re: Troubleshooting USB Ethernet connection [SOLVED]

As a sanity check, if you remove the cable, does the FTDI device in lsusb go missing?

Yeah

Then that cable is not really a cable, it is a dongle.  Specifically it appears to the system as a USB to serial converter. 
It might be that it is doing something clever like using a serial port to talk to an Ethernet MAC (which in turn talks to an Ethernet PHY) and packages all that stuff into one little cable.  If all this is true, then the problem is the kernel is not using the correct driver.  It appears as a serial device, and that is the driver that is being loaded.   There might not even be a proper driver for this in Linux.

Are there any identifying labels on this "cable"?

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Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
The shortest way to ruin a country is to give power to demagogues.— Dionysius of Halicarnassus
---
How to Ask Questions the Smart Way

qherring

Member

Registered: 2023-05-05

Posts: 87

Re: Troubleshooting USB Ethernet connection [SOLVED]

In what order do you plug the cables, first the rj45 or first the USB end? Does it matter? What is the rj45 end plugged into? What if you re-plug that?

Plugged into a 5G router.  I have tried it both ways (laptop first then router, and vise versa) same results. 

Do you get it to get you a carrier on other systems or against other peers?

Could not get a connection through Mac.  Have not tried a windows system yet.  Could just be a dead cable.

qherring

Member

Registered: 2023-05-05

Posts: 87

Re: Troubleshooting USB Ethernet connection [SOLVED]

I used a different adapter and it works fine. 
Avoid this: https://www.amazon.com/gp/product/B082V … UTF8&psc=1

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,727

Re: Troubleshooting USB Ethernet connection [SOLVED]

ummm, that's an RS232 SERIAL adapter, not an ethernet adapter! It's not made to work with a LAN port, it's completely different.