KX-NT556B    KX-NT553B     KX-NT551B


 Specifications KX-NT556  KX-NT553  KX-NT551
 LCD Display   Graphic  Graphic  Graphic
 LCD Size (dots WxH)  242x109  242x55   160x18
 LCD Contrast  4 levels  4 levels  4 levels
 LCD Backlight  On/ Auto/ Off   On/ Auto/ Off   On/ Auto/ Off 
 Install Options
 Desk mount tilt   Yes (2 positions)   Yes (2 positions)   Yes (1 position) 
 Wall mount   KX-A433 (Optional)   KX-A433 (Optional)   (Optional) 
 Power  KX-A239 (Optional)  KX-A239 (Optional)  KX-A239 (Optional)
 Dimensions  High: 267x170x180mm 
 Low: 267x187x155mm
 High: 267x170x180mm 
 Low: 267x187x155mm
 Audio Features
 Handset / Headset
 6 levels  6 levels  6 levels
 Handset   Wideband compliant, 
 Hearing Aid compatibility
 Wideband compliant, 
 Hearing Aid compatibility
 Wideband compliant, 
 Hearing Aid compatibility
 Speaker Phone  Yes (Full Duplex)  Yes (Full Duplex)  Yes (Full Duplex)
 Speaker phone
 8 levels  8 levels  8 levels
 Bluetooth (for headset)  No  No  No
 Ringtones   30  30  30
 Ringer Volume   4 levels + Off  4 levels + Off  4 levels + Off
 Headset port   2.5mm audio jack  2.5mm audio jack  2.5mm audio jack
 Electronic Hook  Switch
  Control Port (EHS) 
 3.5mm Plantronics
 3.5mm Plantronics 
 Audio Codec  G.711, G.722, G.726,
 G.711, G.722, G.726,
 G.711, G.722, G.726,
 Soft Keys  4  4  No
 Programmable Keys   36 (12 keys x 3 pages)  24 (12 keys x 2 pages)  8
 0, 9,*,# Keys   Yes  Yes  Yes
 Navigator & Cancel Key   Yes  Yes  Yes
 (Soft Labelling Keys)
 Yes  Yes  Yes
 Auto Redial   Yes  Yes  Yes
 Off Hook Monitor  Yes  Yes  Yes
 Handset / Headset
 Mic Mute
 Yes  Yes  Yes
 Outgoing - Incoming
  Call Log 
 Yes  Yes  Yes
 Melody Ringer    Yes (10 title)  Yes (10 title)  No
 EcoMode   Yes*³  Yes*³  Yes*³

 Ethernet Ports

 2x 10/100/1000 (Gb)  2x 10/100  2x 10/100
 Power over Ethernet (PoE)  Yes  Yes  Yes
 Bluetooth  Yes (Built in)   No  No
 Firmware upload   Yes  Yes  Yes
 Peer to Peer  connection  Yes  Yes  Yes
 VLAN  Yes  Yes  Yes
 QoS (Diffserv)   Yes*¹  Yes*¹  Yes*¹
 DHCP Client  Yes  Yes  Yes
 VoIP Security  Yes  Yes  Yes
 Ping Transmission  Yes  Yes  Yes
 IP Port Flexibility  Yes  Yes  Yes
 Rerouting to  secondary
 Yes  Yes  Yes
 NAT Traversal   No  No  No
 Media Relay  Gateway  Yes  Yes  Yes
 DSS Console KX-NT505
 LCD  No
 Keys  48
 Connection  Serial I/F to NT550 series
 AC Adaptor  Yes*²
 Installation  Desktop (1 position) Wall mount
 Dimension (WxDxH) mm  High: 137x161x135mm, Low: 137x183x114mm

                 *¹) Only support this feature for packets (PTAP/ MGCP/ RTP) From NT500. The packets of PC Port is sent
                      or received without conversion.
                 *²) AC Adaptor is not necessary for only one module use, but is necessary for 2nd to 4th module.
                 *³) ECO Mode: Setting way method is local programming. Following limitation under ECO Mode:
                      LAN Speed is 10Mbps only, cannot use 2nd port.