All 12 have been tested and are functional, using POE as power.  AC adapter not included.  The phones were able to pull the current time and date thru the POE connection with no prompting from me.  All phones were put to original factory settings. All Phones will come with a CAT cable for POE, stand, handset and phone base.

The Yealink SIP-T53 IP phone is designed for busy executives and professionals. It features 8 lines, a 3.7 inch adjustable display, built-in USB port, Gigabit Ethernet, and HD voice. The SIP-T53 is compatible with the Yealink BT40/BT41 Bluetooth USB dongle and WF40/WF50 Wi-Fi USB dongle so you can add wireless capabilities. It is SIP compatible and can be used with a variety of IP PBX systems and hosted service providers.

Yealink SIP-T53 Features

  • 3.7" 360 x 160 pixel graphical display with backlight
  • Yealink Optima HD Voice
  • Yealink Acoustic Shield technology improves backtround noise suppression when you are using the phone handset or connected headset
  • 8 lines with dual color LED support
  • Up to 12 SIP accounts
  • 5 fixed feature keys - mute, headset, message, redial, speakerphone
  • LED for call and message waiting indication
  • 4-way navigation cluster with 6 navigation keys
  • 4 context sensitive soft keys
  • Volume control
  • Headset port (RJ-9)
  • Built-in a USB 2.0 port compatible with WF40/WF50 WiFi adapter, BT40/BT41 Bluetooth adapter, wired and EHS wireless headsets without the need of the EHS36, and USB call recording via USB flash drive
  • Supports up to 3 Yealink EXP50 expansion modules which can be programmed with up to 180 paperless DSS keys
  • Supports up to 4 DECT cordless handsets via optional DECT Dongle DD10K; can use Yealink W52H, W53H, and W56H wireless handsets
  • Desk stand provides 2 adjustable angles
  • Simple, flexible and secure provisioning options
  • Unified Auto-P template and unified firmware provides simplified management and maintenance
  • Opus codec support - 8kHz (narrowband) and 16 kHz (wideband) sampling rate

Network Connectivity

  • Dual-port Gigabit Ethernet
  • Built-in dual band 2.4/5 GHz Wi-Fi (802.11a/b/g/n/ac)

Power

  • Powered via Power over Ethernet, optional PoE injector, or optional AC adapter