Enclosure Design Requisition

An enclosure is needed for the OSDCU board, a fully open source non-profit SDSL
physical layer interface device.  The desired enclosure type is of the same
general kind as that used by Copper Mountain for their CopperRocket SDSL/IDSL
modem: please examine the supplied CopperRocket sample unit.

This enclosure consists of two specially cut and bent sheet metal pieces.  The
bottom metal piece acts as the baseplate to which the main circuit board and
other system components (see below) are secured, and it also provides the rear
panel through which user-accessible connectors protrude.  The top metal piece
acts as a cover and also provides the front panel with cutouts for LEDs and a
place to put identifying markings.  However, unlike the CopperRocket, the OSDCU
enclosure needs to provide housing for 3 separate components:

* The OSDCU board itself
* An open frame power supply
* An AC power input module

The boardmech.pdf document contains mechanical drawings of the OSDCU board
itself, illustrating all dimensions relevant for fitting into an enclosure.
The open frame power supply used with the OSDCU is Amperor AOF25.  A detailed
mechanical drawing of this part needs to be obtained from Amperor.  The AC
power input module will be either Qualtek P/N 761-18/003 or P/N 762-18/002 from
the same vendor (drawings included in the ZIP archive).  Ideally the enclosure
design should be able to accommodate either part.

The 3 components just listed will be arranged within the enclosure as follows
(schematic drawing not to scale):

+--------------+  +--------------------------------------------------+
|   AC power   |  |                    Connectors                    |
| input module |  |                                                  |
+--------------+  |                                                  |
                  |                                                  |
                  |                                                  |
                  |                                                  |
                  |                   OSDCU board                    |
+--------------+  |                                                  |
|   AC input   |  |                                                  |
|              |  |                                                  |
|     AOF25    |  |                                                  |
|              |  |                                                  |
|  DC output   |  |                       LEDs                       |
+--------------+  +--------------------------------------------------+

The AC power input module shall snap into the rear panel part of the bottom
metal piece, ending up alongside with the OSDCU board's own protruding
connectors.  This module will have an attached internal cable which will plug
into the AC power input connector on the AOF25.

An additional feature which needs to be provided by the *bottom piece* of the
enclosure is ground lead connection.  Qualtek AC power input modules provide an
IEC 320 mains entry (3 leads), whereas the AC power input connector on the AOF25
only has 2 leads.  The OSDCU board expects to get its chassis ground connection
through the copper annuli of its mounting holes, hence this ground connection
needs to be provided via the metal body of the enclosure.  The *bottom piece*
(which holds all components together) needs to feature a grounding stud to which
a wire lead from the AC power input assembly will attach.

Finally, an internal cable will carry DC power from the AOF25 to the OSDCU
board.  The placement of the AOF25 in the enclosure relative to the OSDCU board
should make this connection convenient.
