Controlling time division duplex operation

An intermediate distribution node for digital subscriber line access multiplex, the intermediate distribution node supporting a plurality of subscriber devices and comprising:

• an analogue optical interface for communication of analogue signals for all of the subscriber devices with a central node for digital subscriber line access multiplex;
• a subscriber interface for an electrical subscriber line connection to each one of the subscriber devices;
• an analogue demultiplexer/multiplexer connected between the analogue optical interface and the subscriber interfaces;
• and
• a switch for each one of the subscriber devices, wherein the switch is controllable to selectively enable reception and/or transmission over the respective subscriber interface, controlled using an analogue control signal received from the central node.

A method for controlling an intermediate distribution node for digital subscriber line access multiplex, the method being performed in a central node for digital subscriber line access multiplex supporting a plurality of subscriber devices and comprising the steps of:

• converting incoming digital signals to analogue signals in a plurality of converter devices, for each one of a plurality of subscriber devices wherein each converter device comprises an analogue to digital (A/D) converter and a digital to analogue (D/A) converter;
• generating an analogue control signal for controlling time division duplex operation at the intermediate distribution node;
• multiplexing the analogue downstream signals and the analogue control signal to a combined analogue signal;
• and
• transmitting the combined analogue signal to the intermediate distribution node over an analogue optical interface.