mixed in the same cable. Certain control signals associated with a channel
are generated in the RED area and must be routed to the BLACK area to control
some channel functions. If such signals are routed in the same cable as RED
data, then the signals should be considered RED. Some isolation method must
be incorporated at the RED/BLACK boundary for these signals (see 5.5.2).
220.127.116.11 Sensitive compartmented information facilities (SCIFs). Where
Sensitive Compartmented Information (SCI) is processed in a joint classified
facility, RED SCI cables and other RED cables may use the same wire way or
conduit. Such signals will not be jointly routed in the same cable.
18.104.22.168 Nondevelopmental items (NDIs). Where NDIs are used as RED
processors, the design of such items may not accommodate the use of shielded
cable. In such cases, the designer and installer must exercise extreme
caution in maintaining separation of RED cables. It may be necessary to
distribute cable between NDI equipment separate from all other cables.
5.4.5 Filters and isolators. All lines egressing a facility may require
filters or isolators at the point of egress of the LEA. Within the LEA,
filtering might be used in the equipment design to prevent RFI/EMI. The
designer should be aware of the possible existence of such filtering. In no
case should a line be multifiltered between two points (see 5.5).
22.214.171.124 Filters. Filters are typically housed in RFI tight cabinets.
Cavities within the cabinets have penetrations inward to the equipment, or
outward toward the transmission media, but not both. The filters are firmly
bonded to the walls to assure electrical integrity. Provision must be made
at the entrance of the cabinet to bond and terminate the cable shields. When
selecting filters, the designer must assure the filter impedance is
compatible with the equipment driving the filter (see figure 41). The filter
cabinet must be firmly bonded to the equipotential ground plane.