The attached S-Parameters are recorded in differential to differential configuration with the device at 25 degrees celcius, and a 5V single supply.

The resistor network at the input is included in the S-Parameter measurement (shown in datasheet).

This resistor network is required to set the gain of the device. 

Port 1 - INP
Port 2 - OUTM
Port 3 - INM
Port 4 - OUTP