The 7012 provides 4 rows by 10 columns of 2-pole matrix switching. The
four rows of this card can be connected to the analog backplane within the
7001 or 7002 to make a larger matrix (420) or use it with the 7011 multiplexer
card for greater flexibility through row expansion. Each row is connected
to the backplane with its own jumpers that can be removed to isolate
an individual row from the backplane.
