---
title: "Serial configuration code in data packet"
url: "https://maker.wiznet.io/forum/13212"
markdown_url: "https://maker.wiznet.io/forum/13212/md"
type: "Forum topic"
category: "Serial-to-Ethernet & ConfigTool"
author: "Andy"
created: "2019-02-19T22:18:30+09:00"
last_activity: "2019-02-23T07:22:04+09:00"
language: "en"
views: 561
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Serial configuration code in data packet

## Question

Asked by Andy on 2019-02-19 in Serial-to-Ethernet & ConfigTool.

Hello everyone,

What happens if the 3 bytes of serial configuration code (default “+++”) occur inside a larger data packet? Does wiz-module enter serial configuration mode immediately or can the serial configuration mode only be started, if these 3 bytes are sent in a single datagram to UART?

I am asking, because I often get connection aborts with WIZ110SR (UDP mode, packing condition 1ms), if µC sends many consecutive datagrams (<100bytes each) to UART of wiz-module. (Data is sent binary and encrypted, so each byte combination, i.e. also “+++” is possible in data packet)
In such a case suddenly host does not receive UDP data anymore from wiz-module nor it can send anything to µC so at the end I have to switch power off-on to reset WIZ110SR.
If serial configuration is disabled this never happens, so I assume wiz-module has entered configuration mode accidentally, because “+++” was embedded in data. (not yet logged)
Permanent disabling of serial configuration is unfortunately not a solution for me, so that could become a showstopper for me ![:frowning:](https://emoji.discourse-cdn.com/twitter/frowning.png?v=12)

Regards
Andy

## Replies

### Reply 1 by Andy, 2019-02-23

Hello everyone,

I have checked it and it´s exactly as I was afraid of: If the three magic characters occure anywhere inside data stream, configuration is started at once :-/ My solution: Similar bitstuffing, bytestuffung, i.e. after two consecutive “2B” a redundant byte is inserted by µC and must be removed at host side afterwards before decoding…

Regards
Andy

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Source: https://maker.wiznet.io/forum/13212