Abstract: An interface unit having a digital hierarchy interface function for a communication device has parts disposed on a printed-wiring board in a Layout to maintain desired interface unit characteristics. The interface unit includes a plurality of parallel B/U converter blocks for converting bipolar signals in a plurality of channels into a plurality of unipolar signals, respectively, a plurality of parallel U/B converter blocks for converting unipolar signals in a plurality of channels into a plurality of bipolar signals, respectively, a connector disposed near the B/U converter blocks for connecting the B/U converter blocks to an external device, a shared processor LSI circuit connected to the B/U converter blocks and the U/B converter blocks and disposed near the U/B converter blocks, for interfacing the signals in the channels at a low speed, and a printed-wiring board supporting the B/U converter blocks, the U/B converter blocks, the connector, and the shared processor LSI circuit.

Abstract: This invention relates to a subrack device applicable for an SDH network, and more particularly to a subrack device which can be produced flexibly in response to a customer's need. The subrack device has a subrack body commonly used regardless of a type of the subrack device. The subrack body has a circuit-board-unit housing portion and an outer-connecting-board mounting portion. Circuit boards and outer-connecting-board connecting-boards of different types are prepared. The outer-connecting-board mounting portion has a plurality of outer-connecting-board mounting territories. The outer-connecting-boards are plugged in the outer-connecting-board mounting territories to produce the subrack device meeting the customer's need.