There are 2 types of Digital Integration: APT Integration and DPT Integration.
APT Integration is available when the VPS is connected to a KX-TA624. DPT Integration is available when the VPS is connected to a KX-TD or KX-TA1232 digital PBX.
To the Panasonic KX-TA624, the VPS ports look like proprietary telephones. The PBX thinks that the VPS is a proprietary telephone, and the VPS mimics all actions of a proprietary telephone. Communication between the VPS and the PBX through digital integration requires the proper software level in the PBX and 4-wire connections for each port. To communicate between the VPS and the PBX through APT Integration, the PBX and VPS must be programmed to work together.