Common Backplane; Backplane Location And Physical Description - Nortel Passport 15000 Hardware Description

92 Chapter 3 Shelf assembly

Common backplane

Backplane location and physical description

241-1501-200 5.2S2
This section provides the following information about the shelf assembly
common backplane:
• "Backplane location and physical description" (page 92)
• "Function of the common backplane" (page 93)
The backplane can also be considered a midplane since cards can be inserted
on both sides.
The backplane is located at the rear of the shelf assembly between the
processor cards and the fabrics. The backplane spans both card cages and
extends over the full height and width of the shelf. The backplane is not a
field-replaceable unit. The location of the backplane is shown in the figure:
• "A shelf assembly of a Passport 15000 without fabrics, rear view"
(page 90)
• "A shelf assembly of a Passport 20000 with one fabric removed, rear
view" (page 91)
The backplane of a Passport 15000 is a 20-layer printed circuit board
containing 8 signal layers and 12 power/ground layers. Each processor card
connects to the backplane with 4 Z-PACK connectors with a total of 658 pins
per processor card slot, plus additional pins for the fabric card, MAC address
module, alarm/BITS module, and the power interface modules (PIMs).
Compliant pins are mechanically inserted in the backplane with a friction fit.
The backplane circuit board itself contains no active electronic parts.
The backplane of a Passport 20000 is a 20-layer printed circuit board
containing 10 signal layers, 12 ground, and 2 power layers. Each processor
card connects to the backplane with 4 Z-PACK connectors and 2 power
connectors with a total of 658 pins per processor card slot. This includes pins
for the fabric card, MAC address module, alarm/BITS module, and the power
interface modules (PIMs). Compliant pins are mechanically inserted in the
backplane with a friction fit. The backplane circuit board itself contains no
active electronic parts.