Hi there patfromemerald hills,
You may find the information in the article below helpful.
Apple TV (2nd and 3rd generation): Understanding AirPlay settings
http://support.apple.com/kb/ht5517
Set the security (Apple TV software version 6.1 and later)
Go to Settings > AirPlay > Security.
Use this setting to change the security settings for devices that connect to your Apple TV using AirPlay. You can also set an onscreen code, password, or device verification.
Set an onscreen code
Go to Settings > AirPlay > Security > Onscreen Code > On.
Use this setting to require a specific code to AirPlay to your Apple TV. When Onscreen Code is on and an AirPlay-enabled devices tries to connect to your Apple TV, you must enter the passcode shown on the TV into the device.
Set a password
Go to Settings > AirPlay > Security > Password > [set password]. You can use this setting to require a password for AirPlay-enabled devices to connect using AirPlay on the Apple TV. Use this setting if your device will need permanent access and you only want to enter the password once.
-Griff W.