# Serial port not working\_Proxmox - Node-red

**URL:** <https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439>\
**Category:** General\
**Created:** [22 May 2019 20:45 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439 "2019-05-22T20:45:07Z")\
**Posts on this page:** 19\
**Page:** 1

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [22 May 2019 20:45 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/1 "2019-05-22T20:45:07Z")

</div>

I am running into problems with a USB-serial port. I get the following error while starting node-red.  
22 May 20:31:54 - [error] serial port /dev/ttyUSB0 error: Error: Error: No such file or directory, cannot open /dev/ttyUSB0

I have checked the ports. and it is listed below, only it's not working in node-red. Anyone got some tips?  
lsusb  
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub  
Bus 001 Device 002: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC  
Bus 001 Device 003: ID 8087:0aaa Intel Corp.  
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [22 May 2019 21:06 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/2 "2019-05-22T21:06:19Z")

</div>

Reboot and look in syslog to see what it has connected as. You should see something like

```auto
usb 1-1.3: FTDI USB Serial Device converter now attached to ttyUSB0

```

You should be able to find that after reboot by using the command  
`grep -i serial /var/log/syslog`

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<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [22 May 2019 21:36 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/3 "2019-05-22T21:36:47Z")

</div>

Hi Colin,

This is what I receive

May 22 20:31:37 ProxNodeRed-1 Node-RED[138]: 22 May 20:31:37 - [info] serial port /dev/ttyUSB0 closed  
May 22 20:55:38 ProxNodeRed-1 systemd[1]: Started controls configuration of serial ports.  
May 22 20:55:42 ProxNodeRed-1 Node-RED[139]: 22 May 20:55:42 - [error] serial port /dev/tty error: Error: Error: No such device or address, cannot open /dev/tty  
May 22 20:55:42 ProxNodeRed-1 Node-RED[139]: 22 May 20:55:42 - [info] serial port /dev/tty1 opened at 57600 baud 8N1  
May 22 20:55:42 ProxNodeRed-1 Node-RED[139]: 22 May 20:55:42 - [info] serial port /dev/tty2 opened at 57600 baud 8N1  
May 22 20:56:35 ProxNodeRed-1 Node-RED[139]: 22 May 20:56:35 - [info] serial port /dev/tty closed  
May 22 20:57:11 ProxNodeRed-1 Node-RED[139]: 22 May 20:57:11 - [info] serial port /dev/tty1 closed  
May 22 20:57:11 ProxNodeRed-1 Node-RED[139]: 22 May 20:57:11 - [info] serial port /dev/tty1 opened at 115200 baud 8N1  
May 22 20:57:22 ProxNodeRed-1 Node-RED[139]: 22 May 20:57:22 - [info] serial port /dev/tty2 closed  
May 22 20:57:22 ProxNodeRed-1 Node-RED[139]: 22 May 20:57:22 - [info] serial port /dev/tty2 opened at 115200 baud 8N1  
May 22 20:57:37 ProxNodeRed-1 Node-RED[139]: 22 May 20:57:37 - [error] serial port /dev/tty error: Error: Error: No such device or address, cannot open /dev/tty  
May 22 21:01:50 ProxNodeRed-1 Node-RED[139]: 22 May 21:01:50 - [info] serial port /dev/tty closed  
May 22 21:01:50 ProxNodeRed-1 Node-RED[139]: 22 May 21:01:50 - [error] serial port /dev/ttyUSB0 error: Error: Error: No such file or directory, cannot open /dev/ttyUSB0  
May 22 21:20:55 ProxNodeRed-1 Node-RED[139]: 22 May 21:20:55 - [info] serial port /dev/ttyUSB0 closed  
May 22 21:20:55 ProxNodeRed-1 Node-RED[139]: 22 May 21:20:55 - [info] serial port /dev/tty1 closed  
May 22 21:21:43 ProxNodeRed-1 Node-RED[139]: 22 May 21:21:43 - [info] serial port /dev/tty2 closed  
May 22 21:21:43 ProxNodeRed-1 Node-RED[139]: 22 May 21:21:43 - [error] serial port /dev/tty error: Error: Error: No such device or address, cannot open /dev/tty  
May 22 21:21:54 ProxNodeRed-1 Node-RED[139]: 22 May 21:21:54 - [info] serial port /dev/tty closed  
May 22 21:21:54 ProxNodeRed-1 Node-RED[139]: 22 May 21:21:54 - [info] serial port /dev/tty1 opened at 115200 baud 8N1  
May 22 21:27:10 ProxNodeRed-1 systemd[1]: setserial.service: Failed to reset devices.list: Operation not permitted  
May 22 21:27:17 ProxNodeRed-1 Node-RED[149]: 22 May 21:27:17 - [info] serial port /dev/tty1 opened at 115200 baud 8N1

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<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [22 May 2019 23:07 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/4 "2019-05-22T23:07:23Z")

</div>

Something is pretty seriously wrong I think. Doubt this is a node-red issue.

What device is this? A Pi?

Maybe check the full `dmesg` command output to see any other errors related to serial/usb.

Also `ls -la /dev/t*` and check for the presence of the appropriate dev "files" along with their user/group ownership. On my Pi2, most tty's are owned by root:tty but USB port devices are owned by root:dialout.

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<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [23 May 2019 04:24 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/5 "2019-05-23T04:24:08Z")

</div>

> [@TotallyInformation](#):
>
> ls -la /dev/t\*

Hi Thanks for you feedback.

The device is a a Intel NUC, node-red is running on ubuntu server on Proxmox,

crw-rw-rw- 1 nobody nogroup 5, 0 May 22 20:29 /dev/tty  
crw--w---- 1 root tty 136, 0 May 22 21:27 /dev/tty1  
crw--w---- 1 root tty 136, 1 May 22 21:27 /dev/tty2

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<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [23 May 2019 05:51 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/6 "2019-05-23T05:51:00Z")

</div>

FTDI USB serial devices usually register as /dev/ttyUSB0 1 2 etc. Redo the ls command as sudo. Also redo the grep but try grep usb and grep FTDI instead of serial. See if you can find where it registered. Also you may need to add your user to the dialout group in order to have permission to access the port.

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<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [23 May 2019 06:04 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/7 "2019-05-23T06:04:06Z")

</div>

If that is really all you have, then there is a problem with your installation of Ubuntu I think. Perhaps related to Proxmox which I've never used. Does it actually have access to the physical usb ports?

From what you've shown us so far, no usb port devices are being created. `dmesg` or the commands Dave has mentioned should show that. The full `dmesg` while harder to follow due to volume will show you the full story from boot.

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<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [23 May 2019 06:29 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/8 "2019-05-23T06:29:04Z")

</div>

Thanks for your help, i will try again tonight and let you know what the results are.  
Duncan

---

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [23 May 2019 21:00 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/9 "2019-05-23T21:00:48Z")

</div>

I made a fresh install with a new Ubuntu, still no luck with the serial port. any other sugestions?

pi@Prox-Node-Red:~$ sudo grep -i USB /var/log/syslog  
May 23 20:40:02 Prox-Node-Red Node-RED[541]: 23 May 20:40:02 - [error] serial port /dev/ttyUSB error: Error: Error: No such file or directory, cannot open /dev/ttyUSB  
May 23 20:49:50 Prox-Node-Red Node-RED[414]: 23 May 20:49:50 - [error] serial port /dev/ttyUSB error: Error: Error: No such file or directory, cannot open /dev/ttyUSB  
May 23 20:50:07 Prox-Node-Red Node-RED[414]: 23 May 20:50:07 - [info] serial port /dev/ttyUSB closed

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [23 May 2019 21:05 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/10 "2019-05-23T21:05:40Z")

</div>

What does `lsusb` report ?  
Mine looks like

```auto
Bus 001 Device 003: ID 148f:2770 Ralink Technology, Corp. RT2770 Wireless Adapter
Bus 001 Device 012: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Bus 001 Device 011: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Bus 001 Device 010: ID 05e3:0604 Genesys Logic, Inc. USB 1.1 Hub

```

so you should have an FTDI line at least  
then run `dmesg | grep usb | grep FTDI`  
I get

```auto
usb 1-4.4.4.1: FTDI USB Serial Device converter now attached to ttyUSB2
usb 1-4.4.4.2: FTDI USB Serial Device converter now attached to ttyUSB3

```

So you can see where it installs to... if it does

---

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [23 May 2019 21:22 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/11 "2019-05-23T21:22:33Z")

</div>

> [@dceejay](#):
>
> dmesg | grep usb | grep FTDI

This is what I get but it still doesnt work in node-red?

pi@Prox-Node-Red:/dev$ dmesg | grep usb | grep FTDI  
[2.297350] usb 1-3: Manufacturer: FTDI  
[5.248994] usbserial: USB Serial support registered for FTDI USB Serial Device  
[5.253192] usb 1-3: FTDI USB Serial Device converter now attached to ttyUSB0  
[1313.769642] usb 1-3: Manufacturer: FTDI  
[1313.772794] usb 1-3: FTDI USB Serial Device converter now attached to ttyUSB0  
[1860.073540] usb 1-2: Manufacturer: FTDI  
[1860.076697] usb 1-2: FTDI USB Serial Device converter now attached to ttyUSB0  
[2879.710561] usb 1-3: Manufacturer: FTDI  
[2879.713528] usb 1-3: FTDI USB Serial Device converter now attached to ttyUSB0  
[89372.475172] usb 1-4: Manufacturer: FTDI  
[89372.478246] usb 1-4: FTDI USB Serial Device converter now attached to ttyUSB0

---

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [23 May 2019 21:25 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/12 "2019-05-23T21:25:46Z")

</div>

I only see the tty1 files, and no USB  
pi@Prox-Node-Red:/dev$ ls  
console core fd full initctl log mqueue null ptmx pts random shm stderr stdin stdout tty tty1 tty2 urandom zero  
pi@Prox-Node-Red:/dev$ lsusb  
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub  
Bus 001 Device 007: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC  
Bus 001 Device 003: ID 8087:0aaa Intel Corp.  
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [23 May 2019 21:29 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/13 "2019-05-23T21:29:54Z")

</div>

so you should have a /dev/ttyUSB0  
try `ls -l /dev/ttyUSB0` and  
`sudo ls -l /dev/ttyUSB0`  
and also while we are at it `groups`

---

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [24 May 2019 04:34 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/14 "2019-05-24T04:34:57Z")

</div>

Hi dcejay, I don't have /dev/ttyUSB0?

Last login: Thu May 23 21:20:04 2019 from 192.168.1.109  
pi@Prox-Node-Red:~ ls -l /dev/ttyUSB0 ls: cannot access '/dev/ttyUSB0': No such file or directory pi@Prox-Node-Red:~ sudo ls -l /dev/ttyUSB0  
[sudo] password for pi:  
ls: cannot access '/dev/ttyUSB0': No such file or directory

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [24 May 2019 06:08 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/15 "2019-05-24T06:08:12Z")

</div>

OK . reboot with adapter plugged in. Then run `groups` and then `sudo ls /dev/ttyU*`

---

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [24 May 2019 19:44 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/16 "2019-05-24T19:44:43Z")

</div>

dceejay,

This is the result. Because the Ubuntu is running on a Proxmox VM, is it possible the port isn't mapped from one machine to the other?

pi@Prox-Node-Red:~ groups pi sudo pi@Prox-Node-Red:~ sudo ls /dev/ttyU\*  
[sudo] password for pi:  
ls: cannot access '/dev/ttyU\*': No such file or directory  
pi@Prox-Node-Red:~$

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [24 May 2019 19:59 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/17 "2019-05-24T19:59:27Z")

</div>

Ok. Will hand you over to proxmox folk as it’s not a NodeRed problem

> **[Serial ports on a VM](https://forum.proxmox.com/threads/serial-ports-on-a-vm.2568/)**
>
> Hi.
> Can I access to a physical serial port from a KVM virtual machine, without using a serial network device?

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [24 May 2019 20:43 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/18 "2019-05-24T20:43:50Z")

</div>

Yes, as you will see by looking through `dmesg` from last boot. I think you will find no such devices are created.

---

<div class="post-metadata">

**Author:** ![Duncan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@Duncan](https://discourse.nodered.org/u/Duncan)\
**Post date:** [24 May 2019 20:56 UTC](https://discourse.nodered.org/t/serial-port-not-working-proxmox-node-red/11439/19 "2019-05-24T20:56:45Z")

</div>

Hi Thanks guys for your time and patience. When I solve this problem I will post it here. Maybe it can help someone else.