A midspan unit arranged to supply power to a powered device over data communication cabling constituted of a signal conditioner exhibiting a transfer function with a gain of not less than −0.4 dB as compared with: (K1*(s+R/L1+a)^m)/((s+R/L2+b)^n) over a predetermined frequency range associated with the data transmitted from the powered device. s represents 2*π*(√−1)*f, wherein f represents the predetermined frequency range associated with the data terminal equipment to be powered. R represents the signal source impedance in parallel with the load termination impedance. L1 represents the effective inductance of a data transformer winding of the data transmitter of the powered device, the effective inductance determined responsive to power received by the powered device from the power sourcing equipment; and L2 represents the effective inductance of the data transformer winding of the data transmitter of the powered device expected by a receiver of the switch or hub equipment.