# Serial In/Out Node problem, but working in Arduino serial monitor

**URL:** https://discourse.nodered.org/t/serial-in-out-node-problem-but-working-in-arduino-serial-monitor/97846
**Category:** General
**Created:** [27 June 2025 19:11 UTC](https://discourse.nodered.org/t/serial-in-out-node-problem-but-working-in-arduino-serial-monitor/97846 "2025-06-27T19:11:51Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![AungKL](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@AungKL](https://discourse.nodered.org/u/AungKL)
#### Post date: [27 June 2025 19:11 UTC](https://discourse.nodered.org/t/serial-in-out-node-problem-but-working-in-arduino-serial-monitor/97846/1 "2025-06-27T19:11:51Z")

</div>

Hello dude,

Good day, I have some problem with Serial In/Out node while sending the message to ttyUSB0 of the raspberry pi 4B board.

The setup of the communication is,  
Fluke 289 \<=\> USB IR cable [FT232 chip] \<=\> [ttyUSB0] Raspberry Pi 4B

I've tested with Arduino serial monitor, it's working. I think the setup configuration of Serial In/Out node wrong, please have a look the flow code below.

```auto
[{"id":"8eb05ee13d6eda20","type":"tab","label":"Fluke","disabled":false,"info":"","env":[]},{"id":"21a1db3cd6bcdd43","type":"inject","z":"8eb05ee13d6eda20","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"\"ID\\r\"","payloadType":"json","x":150,"y":200,"wires":[["278f29757591f550"]]},{"id":"ae118b80e88e3db0","type":"debug","z":"8eb05ee13d6eda20","name":"debug 11","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":320,"y":40,"wires":[]},{"id":"2df45364b92a5668","type":"serial in","z":"8eb05ee13d6eda20","name":"","serial":"30c2d68f6909cab4","x":150,"y":40,"wires":[["ae118b80e88e3db0"]]},{"id":"278f29757591f550","type":"serial out","z":"8eb05ee13d6eda20","name":"","serial":"30c2d68f6909cab4","x":390,"y":220,"wires":[]},{"id":"25569a5e7cfeb45f","type":"inject","z":"8eb05ee13d6eda20","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"ID\\r","payloadType":"str","x":150,"y":260,"wires":[["278f29757591f550"]]},{"id":"9006bd492ab61b43","type":"inject","z":"8eb05ee13d6eda20","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"\"ID\"","payloadType":"json","x":150,"y":320,"wires":[["278f29757591f550"]]},{"id":"b2bd62c24d6ca1af","type":"inject","z":"8eb05ee13d6eda20","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"ID","payloadType":"str","x":150,"y":380,"wires":[["278f29757591f550"]]},{"id":"258c2dd342592355","type":"function","z":"8eb05ee13d6eda20","name":"ID\\r","func":"\nmsg.payload = \"ID\\r\";\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":210,"y":160,"wires":[["278f29757591f550"]]},{"id":"4acc986058c8054c","type":"inject","z":"8eb05ee13d6eda20","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":125,"y":160,"wires":[["258c2dd342592355"]],"l":false},{"id":"38788fadce27144a","type":"function","z":"8eb05ee13d6eda20","name":"ID","func":"\nmsg.payload = \"ID\";\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":210,"y":100,"wires":[["278f29757591f550"]]},{"id":"20ca6e6aa4e674b8","type":"inject","z":"8eb05ee13d6eda20","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":125,"y":100,"wires":[["38788fadce27144a"]],"l":false},{"id":"30c2d68f6909cab4","type":"serial-port","z":"8eb05ee13d6eda20","name":"","serialport":"/dev/ttyUSB0","serialbaud":"115200","databits":8,"parity":"none","stopbits":1,"waitfor":"","dtr":"none","rts":"none","cts":"none","dsr":"none","newline":"\\n","bin":"false","out":"char","addchar":"","responsetimeout":10000}]

```

 ![Fluke_2](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/b/e/bea60413f4d8f04f74009d7b96c1cb215fc8172e.jpeg)

 ![Fluke_1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/4/d419b37b03f5323112a1989ee9b934e1f58295c2.jpeg)

Any suggestion or advice would be greatly appreciated.

Best regards,  
Aung

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<div class="post-metadata">

### Author: ![edje11](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/edje11/32/572_2.png) [@edje11](https://discourse.nodered.org/u/edje11)
#### Post date: [28 June 2025 13:30 UTC](https://discourse.nodered.org/t/serial-in-out-node-problem-but-working-in-arduino-serial-monitor/97846/2 "2025-06-28T13:30:19Z")

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No Fluke here, maybe you can give it a try with the **Serial request** node.  
This is the node with IN and OUT.

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<div class="post-metadata">

### Author: ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)
#### Post date: [12 July 2025 13:31 UTC](https://discourse.nodered.org/t/serial-in-out-node-problem-but-working-in-arduino-serial-monitor/97846/3 "2025-07-12T13:31:06Z")

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