The Model 7011 40-channel multiplexer has four independent banks of 1x10 switching. Each channel is 2-pole. These four banks can be combined for a wide variety of switching configurations -- for example, dual 1x20, or 1x10 and 1x30, or one large 1x40. The 7001 mainframe can automatically configure the 7011 to switch 4-pole signals by combining channel pairs. This gives you a dual 1x10 4-pole multiplexer or a single 1x20 4-pole multiplexer.