Motorola MSF 5000 Instruction Manual page 76

Chapter 1 Description
MSF
5000
Instruction Manual
Secure Board
1-38
The Secure board offers several encryption options. These options are available
through the use of various hybrids. Refer to the Secure
Hybrids
section for
additional information on
secure
encryption options.
The Secure board operates
in
one of two programmable
modes of operation. The
first mode of operation is the transparent mode where secure code is detected and
passed directly through the station.
The
Secure board monitors the receiver and
wireline signals until valid
secure code (12 kB/Sec data) is detected. In response,
the Secure board generates a receive or transmit code detect.
During
a code detect,
audio paths on
the
SSCB
are
switched so the secure data is
routed through the Secure board for re-clocking, buffering, and filtering before
being transmitted
and/or
sent out
via
the wireline.
A
Console Interface
Unit
(CIU)
can be interfaced to the station
via
the
wireline
to
provide
the
encrypt/
decrypt capability.
The
second mode
of operation is
the
encrypt/decrypt
mode.
The encryption/
decryption method is determined by
the secure
hybrid option
used.
The
Secure
board provides encryption and decryption of audio signals
in half
or
full-duplex.
During
transmission, audio is
A/D
converted into
a 12
kB/Sec digital
bit
stream
and encrypted. The resultant bit stream is splatter filtered and transmitted.
During
reception, the signal is decoded through
a reverse process.
The
received
encrypted signal is filtered, limited, and re-clocked
to
produce
a
digital
data bit
stream.
The bit stream is decrypted to produce
a
digital
signal. The digital signal
is
D/A
converted into audio. The Full-duplex Wireline option (C332), in
conjunction
with
one
of the secure
hybrid
options, allows simultaneous encrypt
and decrypt operation.
The encryption/ decryption process is performed
by
one
of several different
hybrids,
as
specified
by
the desired
encryption algorithm. Each hybrid is loaded
with
a
different key variable to make
it different from any other hybrid. The
loading
process requires a
Key
Variable Loader (KVL) that interfaces
to the Secure
board through the use of two cables.
The DVP™ is capable of handling four keys maximum
in half
or
full-duplex
mode.
In
half/full-duplex
modes,
a
hybrid
is required for encode/decode
operation.
The
internal secure interface cable
(TKN8597)
connects between the Secure board
(J4001) and the
Junction
Box.
The external
KVL
cable
(TKN8531)
connects
between the
KVL
and the station. When the board is
in half-duplex
operation, up
to
eight hybrids
with
different
key
variables can be selected to perform the
encrypt/ decrypt function. In full-duplex
operation, the
hybrids
are combined
in
pairs
to
provide up to four different encryption/ decryption keys.
68P81092E02
3/14/94
Chapter 1 Description
MSF
5000
Instruction Manual
Secure Board
1-38
The Secure board offers several encryption options. These options are available
through the use of various hybrids. Refer to the Secure
Hybrids
section for
additional information on
secure
encryption options.
The Secure board operates
in
one of two programmable
modes of operation. The
first mode of operation is the transparent mode where secure code is detected and
passed directly through the station.
The
Secure board monitors the receiver and
wireline signals until valid
secure code (12 kB/Sec data) is detected. In response,
the Secure board generates a receive or transmit code detect.
During
a code detect,
audio paths on
the
SSCB
are
switched so the secure data is
routed through the Secure board for re-clocking, buffering, and filtering before
being transmitted
and/or
sent out
via
the wireline.
A
Console Interface
Unit
(CIU)
can be interfaced to the station
via
the
wireline
to
provide
the
encrypt/
decrypt capability.
The
second mode
of operation is
the
encrypt/decrypt
mode.
The encryption/
decryption method is determined by
the secure
hybrid option
used.
The
Secure
board provides encryption and decryption of audio signals
in half
or
full-duplex.
During
transmission, audio is
A/D
converted into
a 12
kB/Sec digital
bit
stream
and encrypted. The resultant bit stream is splatter filtered and transmitted.
During
reception, the signal is decoded through
a reverse process.
The
received
encrypted signal is filtered, limited, and re-clocked
to
produce
a
digital
data bit
stream.
The bit stream is decrypted to produce
a
digital
signal. The digital signal
is
D/A
converted into audio. The Full-duplex Wireline option (C332), in
conjunction
with
one
of the secure
hybrid
options, allows simultaneous encrypt
and decrypt operation.
The encryption/ decryption process is performed
by
one
of several different
hybrids,
as
specified
by
the desired
encryption algorithm. Each hybrid is loaded
with
a
different key variable to make
it different from any other hybrid. The
loading
process requires a
Key
Variable Loader (KVL) that interfaces
to the Secure
board through the use of two cables.
The DVP™ is capable of handling four keys maximum
in half
or
full-duplex
mode.
In
half/full-duplex
modes,
a
hybrid
is required for encode/decode
operation.
The
internal secure interface cable
(TKN8597)
connects between the Secure board
(J4001) and the
Junction
Box.
The external
KVL
cable
(TKN8531)
connects
between the
KVL
and the station. When the board is
in half-duplex
operation, up
to
eight hybrids
with
different
key
variables can be selected to perform the
encrypt/ decrypt function. In full-duplex
operation, the
hybrids
are combined
in
pairs
to
provide up to four different encryption/ decryption keys.
68P81092E02
3/14/94