1. Set WIZ550S2E with Static IP

Set Network IP(192.168.3.101), Subnet Mask(255.255.255.0) and Gateway(192.168.3.1) of WIZ550S2E

<TX> AT+NSET=S,192.168.3.101,255.255.255.0,192.168.3.1\r\n
<RX> [S]\r\n

If you check with AT+NSTAT command after above command, you can get response like below.

<TX> AT+NSTAT\r\n
<RX> [S,,S,192.168.3.101,255.255.255.0,192.168.3.1,168.126.63.1]\r\n

2. Set operating mode of WIZ550S2E with TCP Server mode whose port number is 5000

Create a socket in WIZ550S2E with local port number 5000

<TX> AT+NOPEN=S,5000\r\n
<RX> [S]\r\n

You can check the current status of the socket which you made with AT+NSOCK. Below is an example of it.

<TX> AT+NSOCK=0\r\n
<RX> [S,,S,5000]\r\n

3. a TCP Client connects to WIZ550S2E

When A TCP Client of PC(or any Device) PC connected to WIZ550S2E, you will get a message from WIZ550S2E like below

<RX> [V,0,0]\r\n

4. Send data to TCP Client

If you send 5 bytes data “Hello” to TCP Client with AT+NSEND like below, you will get two step response, Wait Response and Success Response.
[W, 0] means that WIZ550S2E recognized and is processing the command but it is not completed yet. And '0' means socket ID.

<TX> AT+NSEND=0,5\r\nHello
<RX> [W,0]\r\n[S,0]\r\n

5. Receive data “Hi” from TCP Client

If TCP Client sends 2 bytes data “Hi”, then you will get response from WIZ550S2E like below

<RX> [R,0,2]\r\nHi\r\n

6. Disconnect current TCP connection

Do send command like below to disconnect current connection.

<TX> AT+NCLOSE=0\r\n
<RX> [W,0]\r\n[S,0]\r\n

After above command, if you check the status of socket with AT+NSOCK command then you will get response like below.

<TX> AT+NSOCK=0\r\n
<RX> [S,,I]\r\n

Appendix
<Changing mode from Data mode to Coomand mode>

<TX> +++
<RX> \r\n\r\n\r\n[W,0]\r\n[S,0]\r\n (20 Byte)

<Changing mode from Command mode to Data mode>

<TX> AT+MDATA\r\n
<RX> [S]\r\n (5 Byte)