What is difference between Telnet and SSH? Which one is better - Telnet vs SSH?

Telnet and SSH : 

1. TELNET and SSH both are Layer - 7 application layer protocols.

2. Telnet and Ssh both used TCP ( transmission control protocol ) at transport layer.

3.1 Telnet uses Port number 23.

3.2 SSH used port number 22.

4.1 Telnet send all data in Plain Text.

 4.2 Ssh sends all data in Encrypted Format .

=> In telnet all data is send at fast Speed . so telnet is better if you need speed.

=>In Ssh all data is send in encrypted format therefore Ssh is slow protocol and SSH is used when you want security for a device.

So Depends upon a user needs which protocol you want to use either Telnet or SSH.