Update page 'Command Ping'

Command---Ping.md

@@ -0,0 +1,39 @@
+# PING - Command
+
+## Description
+
+The **PING** command is used to check if a remote is responding.  
+It should always be sent as the first command for testing purpose, a connection should  
+be terminated after a failed **PING** request.
+
+## Request
+
+| Command | Argument |
+| :-----: | :------: |
+|  PING   |  Ping*   |
+
+- **Ping**: can be anything
+
+## Response
+
+| Command | Argument |
+| :-----: | :------: |
+|  PING   |  Pong*   |
+
+- **Pong**: exactly the same value as the received Ping
+
+## Example
+
+```md
+PING
+Hello World!
+```
+
+> Request
+
+```md
+PING
+Hello World!
+```
+
+> Response