Open Source Configurations:

Asterisk™ Configuration for IP Phones
Asterisk™ Configuration for GXP Series IP Phones
Asterisk™ Configuration with BLF for GXP2000
Asterisk™ Configuration for GXW410x FXO IP Analog Gateways
Configuring GXW410x with trixbox
Asterisk™ Configuration for GXV3000 IP Video Phone