# usb-Serial-port:how to send a message with hex for RTU Modbus?
**URL:** https://discourse.nodered.org/t/usb-serial-port-how-to-send-a-message-with-hex-for-rtu-modbus/35572
**Category:** General
**Created:** [9 November 2020 03:34 UTC](https://discourse.nodered.org/t/usb-serial-port-how-to-send-a-message-with-hex-for-rtu-modbus/35572 "2020-11-09T03:34:53Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Davidtsai](https://discourse.nodered.org/u/Davidtsai)
#### Post date: [9 November 2020 03:34 UTC](https://discourse.nodered.org/t/usb-serial-port-how-to-send-a-message-with-hex-for-rtu-modbus/35572/1 "2020-11-09T03:34:54Z")
Dear all :
I am use node red serial output to send a message to our modbus device and use python to send message to our modbus device is OK , but when I am use node red serial output or request to send the same message as below ,it send the message but change the type ,how do i send a message as hex .
0: 0xb
1: 0x6
2: 0x8
3: 0x2b
4: 0x0
5: 0x20
6: 0x7a
7: 0xdd
modbus show message as below
2020/11/9 11:03:32.085 [RX] - 7B 22 70 61 79 6C 6F 61 64 22 3A 7B 22 74 79 70 65 22 3A 22 42 75 66 66 65 72 22 2C 22 64 61 74 61 22 3A 5B 31 31 2C 36 2C 38 2C 34 33 2C 30 2C 35 30 2C 31 32 32 2C 32 32 31 5D 7D 79 74 72 71 65
thank you for your help
David best regards
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [8 January 2021 03:35 UTC](https://discourse.nodered.org/t/usb-serial-port-how-to-send-a-message-with-hex-for-rtu-modbus/35572/2 "2021-01-08T03:35:10Z")
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