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MSF
5000
Instruction Manual
Chapter
1
Description
Secure Hybrids
Secure
Board Functional Description
Secure
Hybrid Operation
In the
encrypt/ decrypt
mode of operation, the Secure board supports up to
eight
hybrids.
A
single hybrid can operate in
the
encrypt (transmit)
or
decrypt (receive)
mode, but not in both modes
at the
same time.
Control signals configure
the
hybrids
to either
encrypt
or decrypt.
Figure
1-20
shows
a
block diagram of
the
hybrids
and how they interact
with
the Secure board.
TO RX
AUDIO
CIRCUITRY
FROM
KVL
(VIA J4001)
TO/FROM
MICRO-
PROCESSOR
AND
ACIS
FROM
TX
AUDIO
CIRCUITRY
CLEAR
CODED RX
AUDIO
RX
DATA
RX
AUDIO
CvsD
HYBRIDS
TX
DATA
A
A
CLEAR KEY
CONTROL LINES
KEY
LOADER
CLEAR
CVSD
TX
AUDIO
HYBRIDS
TX
DATA
FULL DUPLEX
CODED
TX
AUDIO
#1
ONLY
MSFI075
030194JNM
Figure 1-20
Secure
Hybrid
68P81092E02
3/14/94
During full-duplex
or
DVP
half-duplex operation,
the
"A"
hybrids
are
configured
to encrypt. These
hybrids
are
located in
the
upper half of
the
hybrid
sockets.
The
lower portions
of the sockets contain the
"B" hybrids, which
share
common
control lines and operate independently from the
"A"
hybrids. The
"B" hybrids
are
configured
to
decrypt during full-duplex
or
DVP
half-duplex
operation.
The current hybrid
selection is
displayed in
the
Key digit
on the Status display.
Hybrid
selection is accomplished through software control, based on information
provided by
the
HSR
signal. The hybrid selection originates
with
user definable
function
tones on the station
wireline;
or locally,
via
the
Control Tray front panel
Select Set switch, when the station is
in
access disable.
The
current
hybrid
selection is
displayed
on the
Key digit
of the
SSCB
front panel
Status display. The
key
selection is used
to
select the
hybrids shown in Table
1-9.
Refer
to the
Key
Variable Loader Interface
section for
key insertion and loading
information.
1-45
MSF
5000
Instruction Manual
Chapter
1
Description
Secure Hybrids
Secure
Board Functional Description
Secure
Hybrid Operation
In the
encrypt/ decrypt
mode of operation, the Secure board supports up to
eight
hybrids.
A
single hybrid can operate in
the
encrypt (transmit)
or
decrypt (receive)
mode, but not in both modes
at the
same time.
Control signals configure
the
hybrids
to either
encrypt
or decrypt.
Figure
1-20
shows
a
block diagram of
the
hybrids
and how they interact
with
the Secure board.
TO RX
AUDIO
CIRCUITRY
FROM
KVL
(VIA J4001)
TO/FROM
MICRO-
PROCESSOR
AND
ACIS
FROM
TX
AUDIO
CIRCUITRY
CLEAR
CODED RX
AUDIO
RX
DATA
RX
AUDIO
CvsD
HYBRIDS
TX
DATA
A
A
CLEAR KEY
CONTROL LINES
KEY
LOADER
CLEAR
CVSD
TX
AUDIO
HYBRIDS
TX
DATA
FULL DUPLEX
CODED
TX
AUDIO
#1
ONLY
MSFI075
030194JNM
Figure 1-20
Secure
Hybrid
68P81092E02
3/14/94
During full-duplex
or
DVP
half-duplex operation,
the
"A"
hybrids
are
configured
to encrypt. These
hybrids
are
located in
the
upper half of
the
hybrid
sockets.
The
lower portions
of the sockets contain the
"B" hybrids, which
share
common
control lines and operate independently from the
"A"
hybrids. The
"B" hybrids
are
configured
to
decrypt during full-duplex
or
DVP
half-duplex
operation.
The current hybrid
selection is
displayed in
the
Key digit
on the Status display.
Hybrid
selection is accomplished through software control, based on information
provided by
the
HSR
signal. The hybrid selection originates
with
user definable
function
tones on the station
wireline;
or locally,
via
the
Control Tray front panel
Select Set switch, when the station is
in
access disable.
The
current
hybrid
selection is
displayed
on the
Key digit
of the
SSCB
front panel
Status display. The
key
selection is used
to
select the
hybrids shown in Table
1-9.
Refer
to the
Key
Variable Loader Interface
section for
key insertion and loading
information.
1-45
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