---
title: "Serial port command operating on WIZ752SR-125"
url: "https://maker.wiznet.io/forum/13184"
markdown_url: "https://maker.wiznet.io/forum/13184/md"
type: "Forum topic"
category: "Serial-to-Ethernet & ConfigTool"
author: "Georgij Batyuchenko"
created: "2019-01-25T08:23:05+09:00"
last_activity: "2019-12-16T01:16:54+09:00"
language: "en"
views: 659
replies: 2
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Serial port command operating on WIZ752SR-125

## Question

Asked by Georgij Batyuchenko on 2019-01-25 in Serial-to-Ethernet & ConfigTool.

Hello.
I am using WIZ752SR-125 and need to configure WIZ752SR throught RS232 port. I’ve enabled `Serial command mode` check box in Windows config tool and set `Trigger code` to 2B 2B 2B. Then I’ve connected RS232 cable (com-0-com) from my desktop to RS232-1 on WIZ board. I send and recieve messages beetwen tcp and RS232 througth configured port. But nothing happens when I try send command for switching port from data mode to command mode.
According command manual from Wizwiki my actions are:
I send SS+++\r\n, by serial port terminal.
Then I try to send SS\r\n or LI\r\n, but there is no effect. Requests apear on socket side and board does not answer.

May be I do something incorrect?

## Replies

### Reply 1 by JamesMassey, 2019-12-13

I think you need a null modem cable between the WIZ752SR-125 and your PC

James

### Reply 2 by lawrence, 2019-12-16

Hi, [@Georgij_Batyuchenko](https://maker.wiznet.io/u/georgij_batyuchenko)

SS command is used to read current trigger code or write new trigger code.

To enter command mode from data mode, you need to send trigger code, +++.
And to enter data mode from command mode, you need to send command, EX.

![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/3/399436680f9bac7333de5f25bb847bb57a518543.png)

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Source: https://maker.wiznet.io/forum/13184