AT&T 4-Line Cordless deskset features extension to extension and base to extension push-to-talk intercom and also offers call transfer capability. Deskset supports 3-way conferencing and comes with volume control and call forwarding options.Features. Component of SynJ Cordless Business Phone System. Supports 4 Lines and Up to 11 Users. 1-to 4-Line Capability. Built-in DECT 6.0 Technology-Up to 10 Cordless Desksets and Accessory Handsets Active at a Time. Up to 12 Mile Extended Range. Push-to-Talk Intercom-From Base to Extension and from Extension to Extension. Intercom and Call Transfer Between Extensions and Base Station. 10 Speed Dial and 10 Intercom Number Locations. 3-Party Conferencing. Speakerphone. Selectable Ringer Tones. Deskset Speakerphone Headset and Ringer Volume Control. Last 10 Number Redial. 100 NameNumber Phonebook Directory. Blue Backlit Display. EnglishSpanish Setup Menu US. EnglishFrench Setup Menu CAN. Mute. Hold. Chain Dialing. Headset Compatible 2.5 mm. jack