Innovative Telecom SX8800-4LPS Music & Message On Hold Adapter with 256MB USB Flash Drive Player Superior sound quality with provided USB drive/ mp3 player or any other audio source Compatible with corded, cordless phones and caller ID, call waiting, 3 way calling, centrex lines and answering machines Compatible with all phone services from all phone companies plus cable, VOIP, MJ, Vonage & FIOS Provides audio test functions, background audio option and customized configuration settings via simple slide switches 5 year parts & labor warranty Use with ordinary analog and KSU-Less phone systems Audio test mode to monitor external audio connected. External audio input connector allows live audio from Radio, XM, Digital Player, etc. Requires no phone handset attachments No moving parts - 100% digital Can be set to support any telephone via FLASH button with instant activation as well (in that case Flash-Flash is used for call waiting, Centrex transfer, 3 way call etc.) Configuration slide switch allows many customizations Two 3 position slide switches for standard telephones configuration setting Both input and output telephone jacks for easy installation LED status lights to indicate lines in use or on Hold Isolated Audio Input rca jack 2 RJ14 phone cords, USB drive/player, USB charger, AC adapter, rca-3.5 mm audio cable and manual all included