Depending on your device and key mappings you have defined, this screen may have slightly different behaviour.
For phones without a full keyboard, or phones with a full keyboard and local input enabled, pressing any key will place the cursor into the local input area.
When the cursor is inside the local input area, further keypresses will type characters into the local input area.  When you want to send these characters to the server, select 'Send' or 'Send with Enter' from the menu, or press the Enter key (if present on your phone).

The following menu items are available (some may not be present depending on your device):

!Enable/Disable Scrolling! - If scrolling is enabled, the direction pad on your phone will scroll the text on the screen.  If scrolling is disabled, the direction pad will send cursor keypresses to the server

!Enable/Disable Local Input! (phones with full keyboards only) - Enables or disables local input.

!Show/Hide Status Bar! (phones without full keyboards) - Determines if the status bar at the bottom of the screen is visible.  Hiding the status bar will provide you with more space to view your session on the screen.  If the status bar is shown, the local input buffer will replace it while your are typing.  
Otherwise, the local input buffer will appear at the bottom of the screen as needed, and the visible area of the screen will be smaller while you are typing.

!Input! (phones without full keyboards) - Places the cursor in the local input buffer.

!Send Enter! (phones without full keyboards) - Sends an enter keypress to the server.

!Ctrl+! - Allows you to send a Ctrl+Character keypress to the server. Type the character, then select 'Send' from the menu.

!Alt+! - Allows you to sent an Alt+Character keypress to the server.  Type the character, then select 'Send' from the menu.

!Special Keys! - Displays the special keys screen, allowing you to send keys such as F1, TAB, and Field Next.

!Disconnect! - Disconnects from the server.