The PC utility software (USW) and the service cable is needed to connect PPM-3 with PC.

The USW is the software that is installed on the PC, notebook or desktop computer and is used for configuration of the PPM-3 & other Multi-line 2 products.

The USW is normally obtained from DEIF website:

Service cable is a normal Printer to USB port (USB A to USB B 2.0) cable easily available in the market.

Video showing how to download the USW: 
FAQ - How to download the utility software for ML-2 products - YouTube