Communication device

A communication device for performing communication control, comprising:

• a detachable card unit for processing signals;
• a basic unit constituted by a basic board having a common control section packaged thereon, and a basic back wiring board on which are arranged a basic card connector for mounting the card unit and a basic link connector for additionally connecting the card unit and which has wiring formed on a substrate thereof;
• and
• an extension unit including an extension back wiring board on which are arranged link connectors detachably connectable to the basic link connector or the link connector of another extension unit, and a card connector for mounting the card unit and which has wiring formed on a substrate thereof, thereby permitting an additional connection for a card unit,
• wherein said extension back wiring board of said extension unit has wiring configured in a manner such that a first pin blcok of an input side link connector is connected to said card connector of the extension unit, and that a second pin block of said input side link connector, other than the first pin block, is connected to a pin block position shifted by one block of an output side link connector.