PDP11 PeripheralsHbk 1972 - Trailing-Edge

2.4.2.5 External Device Cables-An edge connector mounted on the device control
module permits connection to external devices. An H807 36-pin module socket
may be mounted on the device control module and an M927 cable connector or
M925 Flexprint ribbon connector may be used. The M927 is used for coaxial cables
or twisted pairs and is electrically equivalent to the M904 connector; however,
the cable is mounted at the edge of the module card rather than at the end. The
M925 is similar to M903 and is used for Flexprint connectors.
2.4.3 BAll Mounting Boxes
The BAll Mounting Box (see Figure 2-33) is! designed to house the system units
that make up a PDP-ll System. The box also includes space for mounting the
H720 System Power Supply. The mounting box contains fans for forced air cooling,
an insulated top cover (not shown) to prevent debris from falling into the
wire-wrap pins (this is necessary because the system units are mounted with the
pins up and the modules down), and a foam-lined bottom cover, which serves as a
module retainer and minimizes module vibration. The bottom cover serves as part
of the air plenum to ensure adequate cooling.
Figure 2-30 BAll Mounting Box (with wired System Units and H720 Power Supply
installed)
The mounting box is fabricated from zinc-plated steel to resist corrosion. The four
available models are listed in Table 2-11.
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