# Loss of first byte in data transfer

**URL:** <https://forum.arduino.cc/t/loss-of-first-byte-in-data-transfer/1455079>\
**Category:** Programming\
**Created:** [August 8, 2026, 8:32pm UTC](https://forum.arduino.cc/t/loss-of-first-byte-in-data-transfer/1455079 "2026-08-08T20:32:53Z")\
**Posts on this page:** 1\
**Showing post:** 55

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**Author:** ![InquisitiveMind](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/inquisitivemind/32/1272398_2.png) [@InquisitiveMind](https://forum.arduino.cc/u/InquisitiveMind)\
**Post date:** [August 10, 2026, 2:07pm UTC](https://forum.arduino.cc/t/loss-of-first-byte-in-data-transfer/1455079/55 "2026-08-10T14:07:49Z")

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> [@GolamMostafa](#):
>
> We need to resolve the issue

I recently had exactly this issue in another project [DS3231 Service Tool](https://forum.arduino.cc/t/ds3231-service-tool/1451989) where I was entering data manually via the Serial Monitor.

There the line ending setting really mattered, because pressing **Send** could append `\n`, `\r`, both, or nothing, and my receiving code had to deal with that accordingly.

But I think that actually illustrates @UKHeliBob's point here: that was a **manual Serial Monitor input** problem.

In this project the data is sent automatically from one MCU to another. So the Serial Monitor line ending setting is not involved at all. What matters is simply what the transmitting code actually sends and what the receiving code defines as the message terminator.

**Edit:** If the MCU is the sender, as in my project [SerialLED](https://forum.arduino.cc/t/serialled-optical-serial-communication-using-an-onboard-or-external-led/1454912), there is of course no Serial Monitor line-ending setting involved. The transmitting code itself defines exactly which line ending is sent.

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