A line interface board, comprising a plurality of subscriber line interface circuits, an operating mode of which is controlled by mode control signals from a control circuit, wherein each subscriber line interface circuit comprises a plurality of latches which are interconnected between the control circuit and the subscriber line interface circuit, and the latches are adapted to latch the mode control signals received from the control circuit in response to latch enable signals received from the control circuit and to apply those latched mode control signals to the subscriber line interface circuit to control its operating mode, and the latches of each subscriber line interface circuit are series connected and adapted to receive the mode control signals via a common single line.