The GXP16xx series encompasses 6 different devices, all largely the same in terms of functionality, but with some core differences. They are listed below...
GXP1610 - 1 SIP user only, 2 line keys, No PoE Support
GXP1615 - 1 SIP user only, 2 line keys, PoE Support
GXP1620 - 2 SIP User accounts, 2 line keys, No PoE Support
GXP1625 - 2 SIP User accounts, 2 line keys, PoE Support
GXP 1628 - 2 SIP User accounts, 2 line keys, 8 BLF keys, PoE Support
GXP 1630 - 3 SIP User accounts, 3 Line Keys, 8 BLF keys, PoE Support
PoE stands for Power over Ethernet, indicating the ability of the device to obtain its power source via the ethernet (network) cable plugged into the device. This also requires a PoE enabled switch, to supply the power to the phone.
We only directly support the GXP1610 to GXP1625 models and these are the models we can supply to customers.