1-10. Location and Description of Major Components - Continued.
Different models of the TD-1337(V)/G family are achieved by variations in plug-in card usage, presence
or absence of red CESE assembly, and presence or absence of certain rear connectors. Front panel,
power supply, backplane and its wiring, and case are identical for all four models.
Identification Plate. Provides model of TD-1337(V)/G in use.
Case. Welded enclosure that provides mounting facilities for all TD-1337(V)/G subassemblies. Open-
ings on each side of case allow forced air from rack ducting to pass through card file area for
plug-in card cooling. Openings (intake and exhaust) are covered with honeycomb electromagnetic
Front Pane/ A23. All controls and indicators used during operation and organizational maintenance
are on front panel A23. A connector that interfaces the H-250 handset is also located on the front
panel. Display card A23A1 is secured to the rear surface of the front panel and includes displays
that are visible through a window on the front panel. Keyboard A23A2 is located below the display
window and is used to enter instructional data or cause messages to be displayed.
Top Cover. Access to plug-in cards is obtained by removing top cover from case. Top cover is
secured to case by turnlock fasteners that are captive to the rover. Rubber pads located on underside
of the top cover press against the plug-in cards to ensure that the cards remain seated in their
connectors when top cover is installed.
Plug-in Cards. Plug-in cards are assigned reference designators A1 through A22. Each TD-1337(V)/G
model contains a different complement of plug-in cards. The facing illustration lists and illustrates
which plug-in cards are used and where they are installed in each model.
Card File A24. Card file A24 is a rigid framework that houses the plug-in cards. A backplane,
which is part of the card file, contains connectors into which the plug-in cards are installed. These
connectors are assigned reference designators XA1 through XA22. Interconnection wiring and power
distribution busses are located on bottom side of backplane. Polarizing keys are an integral part
of the backplane. The plug-in cards contain cutouts which engage with polarizing keys to ensure
that correct type plug-in card is installed into each backplane connector.
Power Supply PS1. Power supply PS1 is mounted in the upper rear of the case. Screws captive
to the power supply secure the power supply to the case. There is one connector on the bottom
of the power supply that provides electrical interface with the other circuits in the TD-1337(V)/G.
A guide pin located on each side of the connector ensures that the power supply connector mates
properly with the case connector when installing the power supply in the case.
Gaskets. Gaskets are used to provide EMI shielding. A gasket is mounted to the top cover and
provides shielding for the interface between the top cover and the case. Similarity, another gasket
(not shown) is mounted to the bottom cover. Gaskets are also mounted to the case and provide
shielding for the front panel to case interface and the power supply to case interface. You will
be requested to inspect these gaskets when performing certain maintenance procedures in this