This standard defines a general mechanical design implementation for plug-in units. Two types
of plug-in units are defined in this standard. Both Type 1 and Type 2 plug-in units will take
advantage of the increased slot pitch and utilization of the secondary side, as well as enhanced
thermal performance and increased structural durability afforded by this standard. The main
difference between the two types of plug-in units is that the Type 1 plug-in units will have suitable
handling and ESD protection making them compatible with 2 Level Maintenance environments.
Type 2 plug-in units may lack either the required handling and/or ESD protection to make them
fully compatible with 2 Level Maintenance environments.
This standard gives an overview of the associated plug-in units for air cooling, conduction cooling,
liquid cooling, and air flow thru cooling applications. The VITA 48 family of standards defines
applicable detailed dimensions of critical plug-in unit and sub-rack interfaces. The
implementations described in this standard are targeted for 3U and 6U form factor plug-in units
with PCB and backplane electrical connectors defined in VITA 46, with the exception that for
liquid cooling implemented with inboard quick disconnects (QDs) the outer guide sockets will be
replaced with combo QDs. However, in addition to backplane connectors on 0.80 in. centers,
VITA 48 will also define implementations with backplane connectors on 0.85 and 1.00 in. centers