What are the VX1420A/VX1410A/VX1411A intermodule EMI shields for?

What are the VX1420A/VX1410A/VX1411A intermodule EMI shields for?

The intermodule EMI shields are outlined in the VXI specification. The main purpose for these shields is to provide some screening from modules that do not have shields. Since virtually all C-size modules have shields, they are seldom necessary. The shields do have some value for B size modules, since most typically do not have shields. These shields are NOT connected to chassis ground. The VXI specification does not call for grounding, so these shields are isolated on Tektronix and HP mainframes. These shields slide to the left of the unshielded module and are held in place only by gravity and friction. Our card guides have a slit to hold them. If the unprotected module has a front panel, then the front panel would hold the shield in the mainframe. Note that the shield must be installed prior to installing the modules. These shields will NOT work with modules that do not have side shields, (ALL Tektronix VXI modules have shields).

The bottom line is that the EMI blank front panels with EMI fingers and the backplane DIN shields provide more value for most customers.