- The VTech CS6629 DECT 6.0 Expandable Cordless Phone with Caller ID/Call Waiting features a built-in digital answering system. - This phone system includes a backlit keypad and display for easy viewing ECO mode power conserving technology and a quiet mode that silences the ringer to prevent interruption. - The VTech CS6629 DECT 6.0 Expandable Cordless Phone with Caller ID/Call Waiting features a full-duplex handset with speakerphone and a voicemail indicator light for extra convenience. It can be expanded up to 5 total handsets using the VTech CS6609 accessory handset.