TM 11-5895-856-34-1/EE640-CA-MMI-010/ E154 CPU/TO 31W2-2T-122-1
Section VII. PERIPHERAL INTERFACE PANEL
2-25. General
b. A logical ZERO is a signal greater than 3.25
The peripheral interface panel (PIP) in the form of the
volts.
electrical interface panel in the CSCPG provides the
The PIP is located adjacent to the power group in the
power interface between the input 28-vdc bus and the
MSCPG and the electrical interface panel is located
CSCPG power subsystem. (The same function is
adjacent to the power group in the CSCPG. Connectors
performed by the PIP in the MSCPG and, unless
J1 through J54, on the PIP, are provided to connect
otherwise stated, this description applies equally to both
cables from the peripheral equipment to the MSCPG.
units.) 2-26. PIP Interface The PIP also provides the
Connectors J55 through J66 are used to connect the
data and control interface between the IFCUs and the
MSCPG to an external power source. On the electrical
peripheral units associated with the system. Connection
interface panel, connectors J1 through J32 are provided
between the computer and external devices is by
to connect cables from the peripheral equipment to the
twisted-pair signal and return lines. Each signal line is
CSCPG. Connectors J35 through J43 and J17 and J18
terminated by a resistor in the computer and also at the
are used to connect the CSCPG to an external source of
remote end of the line. Each signal line is capable of
power. Signal connectors on both the PIP and the
servicing eight elements in addition to the controlling
electrical interface panel are 55-pin connectors for
element.
Logic levels for the I/O communication
interfacing with the peripheral units, and 80-pin card slot
channel (DC IOE) are as follows:
connectors
for
interfacing
with
the
CPG.
a. A logical ONE is a pulse having a pulse width
greater than 120 nanoseconds and an amplitude less
than 1.5 volts.
Section VIII. DC/DC CONVERTERS
MCMU 1 and MCMU 2, respectively. The remaining ten
2-27. General
converters are identical to each other and provide power
The MSCPG and CSCPG each contain a power
as follows: dc/dc converters A1PS4, AlPS5, and ALPS6
subsystem which provides the necessary operating
provide power to IOU 1, CPU 1A, and CPU 1B,
power to the CPG equipment. These power subsystems
respectively; dc/dc converters AlPS2, A1PS3, A1PS8,
are described in subsequent paragraphs.
and A1PS9 provide the dc operating voltages to IFCU
A, IFCU B, IFCU C, and IFUC D, respectively; and
2-28. MSCPG Power Group
dc/dc converters ALPS10, AIPS11, AlPS12, provide dc
The MSCPG power group (fig. 2-9) contains 12 dc/dc
operating voltages to IOU 2, CPU 2A, and CPU 2B,
converters which provide dc operating voltages to the
respectively.
ALPS1 and AlPS7 each require
CPUs, IOUs, IFCUs, ADP status and control panel, and
approximately 350 watts of primary dc power in order to
MCMUs. The power group receives +28 volts primary
supply dc voltage and current required for MCMU
power via the PIP and produces the dc operating
operation. These converters also contain circuits for
voltages required for MSCPG operation. There are two
orderly MCMU startup and shutdown sequence during
types of dc/dc converters in the power group, two of one
input power on and off transitions.
type and ten of the other. The group of two, A1PS1 and
A1PS7, supply the dc operating voltages for 2-14
2-14
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