A power sourcing equipment-powered device (PSE-PD) combination unit
requests inline power from a connected PSE or other PSE-PD combination
unit by having the PD portion of the PD-PSE combination unit adapt its
electrical characteristics, if necessary, to obtain the maximum power
available. The PD-PSE combination device keeps track of available power
less power consumed locally with a summation unit. A PSE manager unit
grants PD power requests from downstream devices based upon the available
power left (e.g., original PSE power less losses less local consumption).