The SFP+ SR module electrical interface is compliant to SFI electrical specifications. The transmitter input and  receiver output impedance is 100 Ohms differential. Data lines are internally AC coupled. The module provides  differential termination and reduce differential to common mode conversion for Quality signal termination and low  EMI. SFI typically operates over 200 mm of improved FR4 material or up to about 150mmof standard FR4 with one  connector.