Supported by Grandstream's DP750 DECT Base Station; 5 DP720 handsets are supported by each DP750; Supports a range of 300 meters outdoors and 50 meters indoors from the DP750 base station; Supports up to 10 SIP accounts per handset; Full HD audio on both the speakerphone and handset; 3.5mm headset jack, 3-way voice conferencing

Grandstream GXP1625 2 line IP-Phone PoE:2 SIP accounts, 2 line keys, 3-way conferencing, 3 XML programmable context-sensitive soft keys. Dual-switched 10/100 mbps ports, integrated PoE on GXP1625. HD audio on speakerphone and handset. EHS support for Plantronics headsets. Up to 500 contacts, call history up to 200 records. 

Grandstream GXP2140 Enterprise IP Telephone:   

4-line Enterprise HD IP Phone; 480x272 TFT color LCD; Automated provisioning using TR-069 or AES encrypted XML configuration file, TLS/SRTP/HTTPS for advanced security and privacy protection; Integrated real-time web applications [weather, currency, RSS news (pending), etc.]

Grandstream GXP2135 Enterprise HD IP Phone:8 lines, 4 SIP accounts, 4 XML programmable context-sensitive soft keys, Dual switched, auto-sensing Gigabit ports, built-in PoE, 32 digitally programmable and customizable BLF/speed-dial keys, Built-in Bluetooth for syncing headsets and mobile devices for contact books, calendars & call transferring, HD audio on the handset and speakerphone;

Grandstream GXP1630 IP-Phone 2-lines, 8-BLF, Gigabit port:3 SIP accounts, 3 line keys, 4-way conferencing, 3 XML programmable context-sensitive soft keys; HD audio on speakerphone and handset; Dual-switched Gigabit ports, integrated PoE; 8 dual-colored BLF/speed dial keys; EHS support for Plantronics headsets; Up to 500 contacts, call history up to 200 records