---
title: "WIZ750SR data loss at 460800 b/s"
url: "https://maker.wiznet.io/forum/14730"
markdown_url: "https://maker.wiznet.io/forum/14730/md"
type: "Forum topic"
category: "Serial-to-Ethernet & ConfigTool"
author: "may"
created: "2022-11-30T17:54:48+09:00"
last_activity: "2022-12-19T15:20:20+09:00"
language: "en"
views: 369
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# WIZ750SR data loss at 460800 b/s

## Question

Asked by may on 2022-11-30 in Serial-to-Ethernet & ConfigTool.

WIZNET does not provide any software solution to this issue which was raised here many times ( except hiding the 460800 b/s spec in new user manual versions !).
In addition, as the software was written in Keil compiler 5 , it is impossible for the user to fix the bug with the present compiler 6.
Anybody sees a solution ?

## Replies

### Reply 1 by may, 2022-12-17

The data loss is 3 bytes for about 15 kBytes sent to TCP and seems occuring randomly . The probleme is certainly caused by TX buffer unsufficient size The buffer size TX to TCP could be increased by recompiling the software ( rx buffer could be reduced accordingly). Has someone here tested some recompiling ?

### Reply 2 by irina, 2022-12-19 (in reply to reply 1)

![](https://avatars.discourse-cdn.com/v4/letter/n/9fc348/48.png) [WIZ750SR-110 Serial Baudrate](https://forum.wiznet.io/t/topic/5835) [WIZ750 Series](https://maker.wiznet.io/c/serial-to-ethernet-module/wiz750sr-wiz750jr/122)

> Hi, I have two Wiznet S2E modules, one server and the other one is client. There are terminal windows on the serial ends of these two S2E modules. For Baudrate of 115200 the modules transmit data without any errors. But at Baudrate beyond that, for eg. 230400 and above, there are errors during transmission. Is 115200 the max baudrate the WIZ750SR-110 serial interface can run on? Kindly let me know if there is a solution to this. Thank you.

I think this post is similar to your issue.
he default of TCP tx buffer size is 4K. If you want to recompile the code, you can download the code and to change it.

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/7/708538f2745576cfc5ad16bfdfe4ff487027bbe0.png) image1022×458 29.9 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/7/708538f2745576cfc5ad16bfdfe4ff487027bbe0.png)

github: [GitHub - Wiznet/WIZ750SR: WIZnet Serial to Ethernet(S2E) module based on W7500 chip, WIZ107/108SR S2E compatible device](https://github.com/Wiznet/WIZ750SR/)

![:warning:](https://emoji.discourse-cdn.com/twitter/warning.png?v=12) **Caution**

Sn_TXBUF_SIZE configures the TX buffer block size of Socket **n**. Socket **n** TX Buffer Block size can be configured with 1,2,4,8, and 16 Kbytes. If a different size is configured, the data can’t be normally transmitted to a peer.
Although Socket **n** TX Buffer Block size is initially configured to 2Kbytes, user can be re-configure its size using Sn_TXBUF_SIZE. The total sum of Sn_TXBUF_SIZE cannot be exceed 16Kbytes. When exceeded, the data transmission error is occurred.
** n means the number of socket(7) **

### Reply 3 by may, 2022-12-19

Dear Irina,

Thank you for your mail. I found this file size .The problem is thay the Keil compiler does not work in the old version 5, but only version 6 is available now. Here in Toulouse, I didn’t find an aerospace company working with this version 5. In addition So could you recompile it and send it to me ?

( the size should be if I am not wrong 16, 0, 0, 0, 0, 0, 0, 0 )

Best regards

Jean Pierre Mayer

MILLINAV Toulouse France

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Source: https://maker.wiznet.io/forum/14730