3 High-speed subscriber lines according to G.fast standard
3.3 Power supply of optical node from the user modem

In classic analogue and ISDN basic implementing the power of the terminal equipment from the exchange (typically a power supply voltage of 60 V and a supply current of tens of mA). In connection with extreme speed as specified by the working title G.fast is expected to reverse the flow of power.

The node (mini DSLAM) will be power supplied from the local modem in the point that is called as “Distribution point”. The reason for this approach to solving the many years solving problems with power equipment placed in the access network between the PBX (Private Branch eXchange) of telecommunications operator and the subscriber.

Devices in the distribution point is connected to a provider network through optical fiber, so it is not possible to realize the remote power supply by signal line.

Solution of local power supply from a grid is usually problematic. The logical outcome is therefore the power supply from the subscriber side, where it is necessary to summarize the power output from multiple participants at once.