- The AT&T TL90073 Accessory Handset is an accessory handset only- Requires the AT&T TL96273 phone system to operate- Caller ID announce- Push-to-Talk- HD audio with equalizer for customized audio- Simulated full-duplex handset speakerphone- Big buttons- Caller ID/call waiting—50 name and number caller ID history- ECO mode power-conserving technology- Quiet mode- DECT 6.0 digital technology- Intercom between handsets- Conference between an outside line and up to 4 cordless handsets- 200 name and number phonebook directory- Voicemail waiting indicator- Quick access key for voicemail box- Last 10 number redial- English/Spanish/French setup menu- Mute- Any key answer