CX950 Hardware Reference Manual
3-4
3021M100-002
3.2 I/O Section
The Motherboard contains three sets of connectors, each one dedicated to I/O card
interconnection to one of the following busses:
• I/O bus
• PCI bus
• High voltage bus
3.2.1 I/O Bus
In the middle of the motherboard are eight 120-pin card-edge connectors (located
at J12 through J19). They seat the I/O cards in their slots and connect them to the
I/O bus.
3.2.2 PCI Bus
Four 80-pin edge connectors are provided to connect the 32-bit Peripheral
Component Interconnect (PCI) bus to card slots 1 to 4. The PCI bus enables the
high-speed transfer of data between the four card slots and the Motherboard CPU.
The ATM I/O card is PCI 2.1-compliant and is equipped with a proprietary
connector to access the PCI bus.
3.2.3 High Voltage Bus
Voice I/O cards have additional power requirements which are met through the
high voltage bus. This bus carries -12 VDC, -48 VDC, and 86 VAC from the Ring
Generator card (when installed) to the 6-pin high-voltage connectors of each I/O
card slot.
3.3 Power Section
The Motherboard receives +5VDC and +12VDC from one power supply mounted
within the chassis. Two voltages are derived from the +5VDC through voltag
regulators: they are +3.3VDC and +2.5VDC. The +2.5VDC provides power to the
core of the PowerPC.
The Ring Generator card, if installed, provides -12 VDC, -48 VDC, and 86 VAC
to the Analog Voice I/O card, and the Dual Analog Voice (DAV) I/O card.