Service manual

System Overview 1-61
Figure 1–26 is a block diagram of the drawer local I/O riser modules. Together
the two modules, the B4172-Ax and the B4173-Ax, are functionally identical to
the system box local I/O riser module; only the mechanics of the module are
different. In the GS80, the I/O cables must be brought out at a right angle to
the I/O riser. The two-module design makes this possible.
The B4172-Ax plugs into the drawer backplane and the B4173-Ax plugs into the
B4172-Ax module such that the I/O ports exit the back of the drawer.
See the previous section for a description of this module.