Accessory handset only requires a Vtech DS6151 series phone to operate. Two-line operation allows you to dial and receive calls on two different phone lines with one phone. With the touch of a button, the handset speakerphone makes hands-free conversations easy. Know who's calling with Caller ID/call waiting. Handset displays the name, number, time and date of incoming calls. It store 50 calls. The 50-name/number phonebook directory lets you easily store and dial frequently called numbers. With the blue backlit keypad and display, the entire keypad illuminates along with the LCD, allowing easier viewing in dim light. Hearing aid-compatible, RoHS-compliant handset also features any key answer, intercom between handsets, transferring calls between handsets, conferencing between an outside line and up to four cordless handsets, last number redial and selectable-ring tones. Trilingual prompts allow you to choose between English, Spanish and French.