KX-TA824 Features:For 3 CO Lines / 8 Stations Built-In 3x8 with Caller ID For First 3 CO Lines ONLY PC Configuration Software Advanced Hybrid Telephone / Intercom System Expandable Up To 8 CO Lines / 24 Stations -Add 8 Stations (KX-TA82470) -Add 2 CO Lines / 8 Stations (KX-TA82481) -Add 3 CO Lines / 8 Stations (KX-TA82483) Single Line Device Integration* Connect Any Single Line Device (Answering Machines / Cordless Phones / Fax Machines / Modems) *Requires No Additional Cards / Modules Configure System through Phone* or PC (USB) *Phone Must Have LCD Display Network Camera Compatible Voicemail Service Compatible 100 Station Speed Dial Intercom / Paging Call Forward 3-Way Conferencing Room Monitor Background Music Capability -Connect Appropriate Audio Source* -*Audio Source Not Included -Music Stops When Phone Rings -Music Plays to Callers on Hold -Plays on Any Proprietary Phone w/ Built-In Speakerphone Flexible Line Buttons Flexible Ring Assignment* -Set Certain Lines to Ring Only in Certain Rooms -*Only Compatible w/ Panasonic KX-T7731 Outstanding Features: Hybrid System Corded Telephone Speakerphone Key with LED Indication 1-Line Backlit LCD Display Back-Lit Keypad Caller ID / Call Waiting Auto Answer Speakerphone (Intercom) 24 Programmable Line Buttons 12 Line Buttons Equipped With LED"s Message Waiting Indicator Automatic Redial Redial Key Adjustable LCD Contrast Handset / Headset / Speaker Volume Control Hold / Flash / Mute / Store / Message Forward / Do Not Disturb (DND) Pause / Transfer Key Headset Jack Wall MountableKX-TVA50 Features:-Voice Mail With Auto Attendant- Up to 60 Individual Mailboxes- Main Menu w/ Sub Menus- Up To 4 Hours Recording Time