The VTech CS6719-2 Cordless Phone with Caller ID features an expandable system in which you can add up to five additional handsets (uses CS6709). This phone set includes a backlit keypad and display for easy viewing, ECO mode power-conserving technology and a quiet mode that silences the ringer to prevent interruptions. The VTech phone system with call waiting has caller ID, a full duplex handset with speakerphone and an indicator that notifies you of an awaiting voicemail. Handset to Handset Intercom.