# Serial port will not work with cable already plugged in

**URL:** <https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560>\
**Category:** General\
**Created:** [13 July 2018 16:15 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560 "2018-07-13T16:15:13Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [13 July 2018 16:15 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/1 "2018-07-13T16:15:13Z")

</div>

I am using NR on a Raspberry Pi B3+ to display the status of my smart electricity meter (Dutch: "slimme meter") using some form of serial to USB cable (this one: [https://www.sossolutions.nl/slimme-meter-kabel](https://www.sossolutions.nl/slimme-meter-kabel)). This device sends out serial data (approx. one message of a few hundred bytes every second) at a 115200 baud rate.  
Everything works fine, but only if I start NR first and then plugin the cable. If I power up or reboot the Pi and start NR with the cable already attached, NR receives nothing on the serial port. I must then unplug the cable and plug it back in before NR will receive anything on the serial port.  
Is there a way to get this working without needing to unplug the cable every time?

---

<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:** [13 July 2018 21:00 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/2 "2018-07-13T21:00:17Z")

</div>

When it boots with it plugged in is it coming back as the same serial port number as when plugged in later ? Can you check /dev/tty\* to see what is appearing

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [14 July 2018 09:18 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/3 "2018-07-14T09:18:28Z")

</div>

These are the tty devices:

```auto
pi@pimeterkast:~ $ ls -al /dev/tty*
crw-rw-rw- 1 root tty 5, 0 Jul 13 12:17 /dev/tty
crw--w---- 1 root tty 4, 0 Jul 13 12:17 /dev/tty0
crw--w---- 1 root tty 4, 1 Jul 13 12:17 /dev/tty1
crw--w---- 1 root tty 4, 10 Jul 13 12:17 /dev/tty10
crw--w---- 1 root tty 4, 11 Jul 13 12:17 /dev/tty11
crw--w---- 1 root tty 4, 12 Jul 13 12:17 /dev/tty12
crw--w---- 1 root tty 4, 13 Jul 13 12:17 /dev/tty13
crw--w---- 1 root tty 4, 14 Jul 13 12:17 /dev/tty14
crw--w---- 1 root tty 4, 15 Jul 13 12:17 /dev/tty15
crw--w---- 1 root tty 4, 16 Jul 13 12:17 /dev/tty16
crw--w---- 1 root tty 4, 17 Jul 13 12:17 /dev/tty17
crw--w---- 1 root tty 4, 18 Jul 13 12:17 /dev/tty18
crw--w---- 1 root tty 4, 19 Jul 13 12:17 /dev/tty19
crw--w---- 1 root tty 4, 2 Jul 13 12:17 /dev/tty2
crw--w---- 1 root tty 4, 20 Jul 13 12:17 /dev/tty20
crw--w---- 1 root tty 4, 21 Jul 13 12:17 /dev/tty21
crw--w---- 1 root tty 4, 22 Jul 13 12:17 /dev/tty22
crw--w---- 1 root tty 4, 23 Jul 13 12:17 /dev/tty23
crw--w---- 1 root tty 4, 24 Jul 13 12:17 /dev/tty24
crw--w---- 1 root tty 4, 25 Jul 13 12:17 /dev/tty25
crw--w---- 1 root tty 4, 26 Jul 13 12:17 /dev/tty26
crw--w---- 1 root tty 4, 27 Jul 13 12:17 /dev/tty27
crw--w---- 1 root tty 4, 28 Jul 13 12:17 /dev/tty28
crw--w---- 1 root tty 4, 29 Jul 13 12:17 /dev/tty29
crw--w---- 1 root tty 4, 3 Jul 13 12:17 /dev/tty3
crw--w---- 1 root tty 4, 30 Jul 13 12:17 /dev/tty30
crw--w---- 1 root tty 4, 31 Jul 13 12:17 /dev/tty31
crw--w---- 1 root tty 4, 32 Jul 13 12:17 /dev/tty32
crw--w---- 1 root tty 4, 33 Jul 13 12:17 /dev/tty33
crw--w---- 1 root tty 4, 34 Jul 13 12:17 /dev/tty34
crw--w---- 1 root tty 4, 35 Jul 13 12:17 /dev/tty35
crw--w---- 1 root tty 4, 36 Jul 13 12:17 /dev/tty36
crw--w---- 1 root tty 4, 37 Jul 13 12:17 /dev/tty37
crw--w---- 1 root tty 4, 38 Jul 13 12:17 /dev/tty38
crw--w---- 1 root tty 4, 39 Jul 13 12:17 /dev/tty39
crw--w---- 1 root tty 4, 4 Jul 13 12:17 /dev/tty4
crw--w---- 1 root tty 4, 40 Jul 13 12:17 /dev/tty40
crw--w---- 1 root tty 4, 41 Jul 13 12:17 /dev/tty41
crw--w---- 1 root tty 4, 42 Jul 13 12:17 /dev/tty42
crw--w---- 1 root tty 4, 43 Jul 13 12:17 /dev/tty43
crw--w---- 1 root tty 4, 44 Jul 13 12:17 /dev/tty44
crw--w---- 1 root tty 4, 45 Jul 13 12:17 /dev/tty45
crw--w---- 1 root tty 4, 46 Jul 13 12:17 /dev/tty46
crw--w---- 1 root tty 4, 47 Jul 13 12:17 /dev/tty47
crw--w---- 1 root tty 4, 48 Jul 13 12:17 /dev/tty48
crw--w---- 1 root tty 4, 49 Jul 13 12:17 /dev/tty49
crw--w---- 1 root tty 4, 5 Jul 13 12:17 /dev/tty5
crw--w---- 1 root tty 4, 50 Jul 13 12:17 /dev/tty50
crw--w---- 1 root tty 4, 51 Jul 13 12:17 /dev/tty51
crw--w---- 1 root tty 4, 52 Jul 13 12:17 /dev/tty52
crw--w---- 1 root tty 4, 53 Jul 13 12:17 /dev/tty53
crw--w---- 1 root tty 4, 54 Jul 13 12:17 /dev/tty54
crw--w---- 1 root tty 4, 55 Jul 13 12:17 /dev/tty55
crw--w---- 1 root tty 4, 56 Jul 13 12:17 /dev/tty56
crw--w---- 1 root tty 4, 57 Jul 13 12:17 /dev/tty57
crw--w---- 1 root tty 4, 58 Jul 13 12:17 /dev/tty58
crw--w---- 1 root tty 4, 59 Jul 13 12:17 /dev/tty59
crw--w---- 1 root tty 4, 6 Jul 13 12:17 /dev/tty6
crw--w---- 1 root tty 4, 60 Jul 13 12:17 /dev/tty60
crw--w---- 1 root tty 4, 61 Jul 13 12:17 /dev/tty61
crw--w---- 1 root tty 4, 62 Jul 13 12:17 /dev/tty62
crw--w---- 1 root tty 4, 63 Jul 13 12:17 /dev/tty63
crw--w---- 1 root tty 4, 7 Jul 13 12:17 /dev/tty7
crw--w---- 1 root tty 4, 8 Jul 13 12:17 /dev/tty8
crw--w---- 1 root tty 4, 9 Jul 13 12:17 /dev/tty9
crw-rw---- 1 root dialout 204, 64 Jul 13 12:17 /dev/ttyAMA0
crw-rw---- 1 root dialout 188, 0 Jul 13 12:21 /dev/ttyUSB0
crw------- 1 root root 5, 3 Jul 13 12:17 /dev/ttyprintk

```

This list remains the same after a reboot.  
The serial node is configured as `/dev/ttyUSB0:115200-8N1` which is also the same after a reboot.

---

<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:** [14 July 2018 13:31 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/4 "2018-07-14T13:31:28Z")

</div>

Same as my Pi2 settings except for tty1 which I don't _think_ I use:

```auto
crw------- 1 pi tty 4, 1 Jun 29 23:25 /dev/tty1
...
crw-rw---- 1 root dialout 204, 64 Jun 29 23:25 /dev/ttyAMA0
crw------- 1 root root 5, 3 Jun 29 23:25 /dev/ttyprintk
crw-rw---- 1 root dialout 188, 0 Jul 14 08:00 /dev/ttyUSB0

```

I was going to say that I don't have any issues like yours but then I realised I **do** have an issue but it isn't the same. If I have a power brownout (when my UPS switches from mains to battery then back again), the network doesn't reconnect. Don't have that issue on my Pi3 which I will switch to eventually. Not the same problem as I say.

What OS version are you using? And was it a clean install or an upgrade?

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [14 July 2018 14:21 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/5 "2018-07-14T14:21:40Z")

</div>

It was a clean install:

```auto
pi@pimeterkast:~ $ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)"
NAME="Raspbian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

```

---

<div class="post-metadata">

**Author:** ![asandford](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@asandford](https://discourse.nodered.org/u/asandford)\
**Post date:** [14 July 2018 18:18 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/6 "2018-07-14T18:18:58Z")

</div>

What does `lsusb` show?

If it shows nothing about a serial device, unplug and replug the device.

If it then shows FTDI, then there's a problem with some of those not being recognised on boot (typically clone Ardinuios).

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [14 July 2018 18:31 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/7 "2018-07-14T18:31:22Z")

</div>

when running ok:

```auto
pi@pimeterkast:~ $ lsusb
Bus 001 Device 007: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
Bus 001 Device 005: ID 2357:0601  
Bus 001 Device 006: ID 0424:7800 Standard Microsystems Corp. 
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

```

after reboot (not running anymore):

```auto
pi@pimeterkast:~ $ lsusb
Bus 001 Device 004: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
Bus 001 Device 005: ID 2357:0601  
Bus 001 Device 006: ID 0424:7800 Standard Microsystems Corp. 
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

```

after unplugging and plugging in (running ok again):

```auto
pi@pimeterkast:~ $ lsusb
Bus 001 Device 007: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
Bus 001 Device 005: ID 2357:0601  
Bus 001 Device 006: ID 0424:7800 Standard Microsystems Corp. 
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
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:** [15 July 2018 16:03 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/8 "2018-07-15T16:03:46Z")

</div>

Reboot and in a terminal run  
`tail -f -n 1000 /var/log/syslog|grep usb`  
which will show you all the recent usb related messages in syslog and will sit there waiting for more entries, towards the end you should see a line saying that the device has been attached to ttyUSB0 or something similar. Then unplug it, wait a few secs and then plug it in again, I suspect you will then see that it has been attached as something different, possibly ttyUSB1. If this is the case then you need to specify a udev rule to get it to always connect as the same device. Using udev rules is the only reliable way of making sure a usb interface always connects as the same device. But confirm that is actually what is happening first.

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [15 July 2018 17:58 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/9 "2018-07-15T17:58:03Z")

</div>

this is what I see after a reboot:

```auto
Jul 15 19:39:25 pimeterkast mtp-probe: checking bus 1, device 5: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1/1-1.1.3"
Jul 15 19:39:25 pimeterkast mtp-probe: checking bus 1, device 6: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1/1-1.1.1"
Jul 15 19:39:25 pimeterkast mtp-probe: checking bus 1, device 4: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3"
Jul 15 19:39:25 pimeterkast mtp-probe: checking bus 1, device 6: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1/1-1.1.1"
Jul 15 19:39:25 pimeterkast mtp-probe: checking bus 1, device 5: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1/1-1.1.3"
Jul 15 19:39:25 pimeterkast kernel: [0.061322] usbcore: registered new interface driver usbfs
Jul 15 19:39:25 pimeterkast kernel: [0.061373] usbcore: registered new interface driver hub
Jul 15 19:39:25 pimeterkast kernel: [0.061457] usbcore: registered new device driver usb
Jul 15 19:39:25 pimeterkast kernel: [0.211071] usbcore: registered new interface driver lan78xx
Jul 15 19:39:25 pimeterkast kernel: [0.211125] usbcore: registered new interface driver smsc95xx
Jul 15 19:39:25 pimeterkast kernel: [0.640076] dwc_otg 3f980000.usb: DWC OTG Controller
Jul 15 19:39:25 pimeterkast kernel: [0.640106] dwc_otg 3f980000.usb: new USB bus registered, assigned bus number 1
Jul 15 19:39:25 pimeterkast kernel: [0.640138] dwc_otg 3f980000.usb: irq 62, io mem 0x00000000
Jul 15 19:39:25 pimeterkast kernel: [0.640389] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
Jul 15 19:39:25 pimeterkast kernel: [0.640399] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Jul 15 19:39:25 pimeterkast kernel: [0.640407] usb usb1: Product: DWC OTG Controller
Jul 15 19:39:25 pimeterkast kernel: [0.640415] usb usb1: Manufacturer: Linux 4.14.50-v7+ dwc_otg_hcd
Jul 15 19:39:25 pimeterkast kernel: [0.640423] usb usb1: SerialNumber: 3f980000.usb
Jul 15 19:39:25 pimeterkast kernel: [0.641801] usbcore: registered new interface driver usb-storage
Jul 15 19:39:25 pimeterkast kernel: [0.646427] usbcore: registered new interface driver usbhid
Jul 15 19:39:25 pimeterkast kernel: [0.646432] usbhid: USB HID core driver
Jul 15 19:39:25 pimeterkast kernel: [1.061540] usb 1-1: new high-speed USB device number 2 using dwc_otg
Jul 15 19:39:25 pimeterkast kernel: [1.311826] usb 1-1: New USB device found, idVendor=0424, idProduct=2514
Jul 15 19:39:25 pimeterkast kernel: [1.311841] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Jul 15 19:39:25 pimeterkast kernel: [1.631596] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
Jul 15 19:39:25 pimeterkast kernel: [1.781914] usb 1-1.1: New USB device found, idVendor=0424, idProduct=2514
Jul 15 19:39:25 pimeterkast kernel: [1.781930] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Jul 15 19:39:25 pimeterkast kernel: [1.881552] usb 1-1.3: new full-speed USB device number 4 using dwc_otg
Jul 15 19:39:25 pimeterkast kernel: [2.039123] usb 1-1.3: New USB device found, idVendor=0403, idProduct=6001
Jul 15 19:39:25 pimeterkast kernel: [2.039138] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jul 15 19:39:25 pimeterkast kernel: [2.039146] usb 1-1.3: Product: FT232R USB UART
Jul 15 19:39:25 pimeterkast kernel: [2.039154] usb 1-1.3: Manufacturer: FTDI
Jul 15 19:39:25 pimeterkast kernel: [2.039162] usb 1-1.3: SerialNumber: AI1X30AW
Jul 15 19:39:25 pimeterkast kernel: [2.111641] usb 1-1.1.3: new high-speed USB device number 5 using dwc_otg
Jul 15 19:39:25 pimeterkast kernel: [2.243126] usb 1-1.1.3: New USB device found, idVendor=2357, idProduct=0601
Jul 15 19:39:25 pimeterkast kernel: [2.243146] usb 1-1.1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=6
Jul 15 19:39:25 pimeterkast kernel: [2.243155] usb 1-1.1.3: Product: USB 10/100/1000 LAN
Jul 15 19:39:25 pimeterkast kernel: [2.243163] usb 1-1.1.3: Manufacturer: TP-LINK
Jul 15 19:39:25 pimeterkast kernel: [2.243171] usb 1-1.1.3: SerialNumber: 000001000000
Jul 15 19:39:25 pimeterkast kernel: [2.541610] usb 1-1.1.1: new high-speed USB device number 6 using dwc_otg
Jul 15 19:39:25 pimeterkast kernel: [2.672290] usb 1-1.1.1: New USB device found, idVendor=0424, idProduct=7800
Jul 15 19:39:25 pimeterkast kernel: [2.672307] usb 1-1.1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Jul 15 19:39:25 pimeterkast kernel: [3.019314] usbcore: registered new interface driver r8152
Jul 15 19:39:25 pimeterkast kernel: [3.029063] usbcore: registered new interface driver cdc_ether
Jul 15 19:39:25 pimeterkast kernel: [3.111618] usb 1-1.1.3: reset high-speed USB device number 5 using dwc_otg
Jul 15 19:39:25 pimeterkast kernel: [3.469157] usbcore: registered new interface driver brcmfmac
Jul 15 19:39:25 pimeterkast kernel: [3.518737] usbcore: registered new interface driver usbserial
Jul 15 19:39:25 pimeterkast kernel: [3.518805] usbcore: registered new interface driver usbserial_generic
Jul 15 19:39:25 pimeterkast kernel: [3.518872] usbserial: USB Serial support registered for generic
Jul 15 19:39:25 pimeterkast kernel: [3.531302] usbcore: registered new interface driver ftdi_sio
Jul 15 19:39:25 pimeterkast kernel: [3.531389] usbserial: USB Serial support registered for FTDI USB Serial Device
Jul 15 19:39:25 pimeterkast kernel: [3.532085] usb 1-1.3: Detected FT232RL
Jul 15 19:39:25 pimeterkast kernel: [3.533632] usb 1-1.3: FTDI USB Serial Device converter now attached to ttyUSB0

```

The USB interface is attached as `ttyUSB0` (but not working in NR)

after unplugging and replugging, these lines are added to syslog:

```auto
Jul 15 19:42:49 pimeterkast kernel: [201.792246] ftdi_sio ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32
Jul 15 19:42:49 pimeterkast kernel: [201.792359] ftdi_sio ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32
Jul 15 19:42:49 pimeterkast kernel: [201.981394] usb 1-1.3: USB disconnect, device number 4
Jul 15 19:42:58 pimeterkast kernel: [211.234131] usb 1-1.3: new full-speed USB device number 7 using dwc_otg
Jul 15 19:42:58 pimeterkast kernel: [211.391637] usb 1-1.3: New USB device found, idVendor=0403, idProduct=6001
Jul 15 19:42:58 pimeterkast kernel: [211.391655] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jul 15 19:42:58 pimeterkast kernel: [211.391663] usb 1-1.3: Product: FT232R USB UART
Jul 15 19:42:58 pimeterkast kernel: [211.391671] usb 1-1.3: Manufacturer: FTDI
Jul 15 19:42:58 pimeterkast kernel: [211.391679] usb 1-1.3: SerialNumber: AI1X30AW
Jul 15 19:42:58 pimeterkast kernel: [211.400237] usb 1-1.3: Detected FT232RL
Jul 15 19:42:58 pimeterkast kernel: [211.401133] usb 1-1.3: FTDI USB Serial Device converter now attached to ttyUSB0
Jul 15 19:42:58 pimeterkast mtp-probe: checking bus 1, device 7: "/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3"

```

The USB interface is again attached as `ttyUSB0` (and is now working in NR)  
It has now device number 7 instead of 4.  
So, this is not the cause of the problem ?

---

<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:** [15 July 2018 19:13 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/10 "2018-07-15T19:13:48Z")

</div>

> [@willemx](#):
>
> It has now device number 7 instead of 4.  
> So, this is not the cause of the problem ?

Looks like it. I imagine that means that the original is not actually being released.

I suggest that you look up how to give the device a fixed name. I had to do that with one of my devices.

---

<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:** [15 July 2018 19:14 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/11 "2018-07-15T19:14:02Z")

</div>

Apparently not.  
Don't know what else to suggest.

---

<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:** [15 July 2018 19:16 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/12 "2018-07-15T19:16:01Z")

</div>

Something like this maybe?

[http://hintshop.ludvig.co.nz/show/persistent-names-usb-serial-devices/](http://hintshop.ludvig.co.nz/show/persistent-names-usb-serial-devices/)

---

<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:** [15 July 2018 20:56 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/13 "2018-07-15T20:56:08Z")

</div>

It _has_ got a persistent name, it started life as ttyUSB0 and was the same after re-connect.

@willemx what do you see in the node-red log on startup after boot.

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [16 July 2018 07:33 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/14 "2018-07-16T07:33:39Z")

</div>

This is in the journal:

```auto
pi@pimeterkast:~ $ journalctl -u nodered -o cat
Started Node-RED graphical event wiring tool.
15 Jul 19:39:33 - [info]
Welcome to Node-RED
===================
15 Jul 19:39:33 - [info] Node-RED version: v0.18.7
15 Jul 19:39:33 - [info] Node.js version: v8.11.3
15 Jul 19:39:33 - [info] Linux 4.14.50-v7+ arm LE
15 Jul 19:39:35 - [info] Loading palette nodes
15 Jul 19:39:40 - [info] Dashboard version 2.8.2 started at /ui
15 Jul 19:39:42 - [info] Settings file : /home/pi/.node-red/settings.js
15 Jul 19:39:42 - [info] User directory : /home/pi/.node-red
15 Jul 19:39:42 - [warn] Projects disabled : set editorTheme.projects.enabled=true to enable
15 Jul 19:39:42 - [info] Flows file : /home/pi/.node-red/flows_pimeterkast.json
15 Jul 19:39:42 - [info] Server now running at http://127.0.0.1:1880/
15 Jul 19:39:42 - [warn]
---------------------------------------------------------------------
Your flow credentials file is encrypted using a system-generated key.
If the system-generated key is lost for any reason, your credentials
file will not be recoverable, you will have to delete it and re-enter
your credentials.
You should set your own key using the 'credentialSecret' option in
your settings file. Node-RED will then re-encrypt your credentials
file using your chosen key the next time you deploy a change.
---------------------------------------------------------------------
15 Jul 19:39:42 - [info] Starting flows
15 Jul 19:39:42 - [info] Started flows
15 Jul 19:39:43 - [info] serial port /dev/ttyUSB0 opened at 115200 baud 8N1
15 Jul 19:39:43 - [info] [mqtt-broker:localhost] Connected to broker: mqtt://localhost:1883
15 Jul 19:42:49 - [error] serial port /dev/ttyUSB0 closed unexpectedly
15 Jul 19:43:04 - [info] serial port /dev/ttyUSB0 opened at 115200 baud 8N1

```

The serial port was opened first at 19:39:43, but did not receive data.  
The cable was unplugged at 19:42:49 and plugged back in and then data was received.

---

<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:** [16 July 2018 16:32 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/15 "2018-07-16T16:32:22Z")

</div>

Are you definite that it is not the device at the other end that is causing the problem?

---

<div class="post-metadata">

**Author:** ![mako](https://avatars.discourse-cdn.com/v4/letter/m/ecc23a/32.png) [@mako](https://discourse.nodered.org/u/mako)\
**Post date:** [17 July 2018 01:28 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/16 "2018-07-17T01:28:13Z")

</div>

Hi Mate.

Read this. this solved all my serial RS485 issues.  
It may help you.

> **[Configuring The GPIO Serial Port On Raspbian Jessie and Stretch Including Pi 3 -...](https://spellfoundry.com/2016/05/29/configuring-gpio-serial-port-raspbian-jessie-including-pi-3/)**
>
> The Raspberry Pi GPIO serial port configuration has changed under Jessie / Stretch and also with the Raspberry PI 3.This post describes how it is now setup.

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [17 July 2018 15:10 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/17 "2018-07-17T15:10:05Z")

</div>

@Colin  
I don't think the other end is the problem, because when I do

```auto
cu -l /dev/ttyUSB0 -s 115200 --parity=none

```

after a reboot, the serial port starts spitting out data right away:

```auto

pi@pimeterkast:~ $ cu -l /dev/ttyUSB0 -s 115200 --parity=none
Connected.
/Ene5\T210-D ESMR5.0

1-3:0.2.8(50)
0-0:1.0.0(180717170525S)
0-0:96.1.1(4530303438303030303131353534373138)
1-0:1.8.1(002351.055*kWh)
1-0:1.8.2(001640.822*kWh)
1-0:2.8.1(000577.631*kWh)
1-0:2.8.2(001294.589*kWh)
0-0:96.14.0(0002)
1-0:1.7.0(00.000*kW)
1-0:2.7.0(07.518*kW)
0-0:96.7.21(00047)
0-0:96.7.9(00003)
1-0:99.97.0(0)(0-0:96.7.19)
1-0:32.32.0(00003)
1-0:52.32.0(00003)
1-0:72.32.0(00002)
1-0:32.36.0(00000)
1-0:52.36.0(00000)
1-0:72.36.0(00000)
0-0:96.13.0()
1-0:32.7.0(235.0*V)
1-0:52.7.0(234.0*V)
1-0:72.7.0(235.0*V)
1-0:31.7.0(011*A)
1-0:51.7.0(011*A)
1-0:71.7.0(008*A)
1-0:21.7.0(00.000*kW)
1-0:41.7.0(00.000*kW)
1-0:61.7.0(00.000*kW)
1-0:22.7.0(02.709*kW)
1-0:42.7.0(02.733*kW)
1-0:62.7.0(02.075*kW)
!B641
/Ene5\T210-D ESMR5.0

etc, etc, ...

```

---

<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:** [17 July 2018 15:30 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/18 "2018-07-17T15:30:57Z")

</div>

Does it do that even with node-red running? I would have expected it to fail because node-red would be using the port.  
Does that work after you unplug and replug and node-red the port is working in node-red?

---

<div class="post-metadata">

**Author:** ![willemx](https://avatars.discourse-cdn.com/v4/letter/w/a4c791/32.png) [@willemx](https://discourse.nodered.org/u/willemx)\
**Post date:** [17 July 2018 15:43 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/19 "2018-07-17T15:43:29Z")

</div>

Yes, `cu` works even when node-red is running.  
If node-red is running and I have unplugged and replugged the cable (so node-red is receiving data) and then I start `cu`, node-red will stop receiving data.  
And then, if I stop cu, node-red will "take back" the serial port and will receive data again.

---

<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:** [17 July 2018 20:08 UTC](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560/20 "2018-07-17T20:08:36Z")

</div>

How have you got the serial port configured in node-red?

[Next page](https://discourse.nodered.org/t/serial-port-will-not-work-with-cable-already-plugged-in/1560.md?page=2)