MULTI-NET SYSTEM OVERVIEW
5-9
Revised February 1997
Part No. 001-9750-005
5.8.16 VOICE ENCRYPTION
NOTE: Voice encryption is currently not available for
E.F. Johnson 900 MHz transceivers.
Optional voice encryption provides security from
unauthorized monitoring of conversations by casual
eavesdropping and analog scanners. Multi-Net encryp-
tion employs Continuous Sync™ technology to
provide fast synchronization and decoding of
messages. This means that calls can be received even
if the transceiver is turned on in the middle of a
message or if a call is entered from the scan mode.
Encryption encodes the audio signal using a
special code sequence. Over five-billion different
codes are available, and only other mobiles with the
same code sequence can receive a call. Encryption is
available on both group and telephone calls (either
mobile- and landside-originated). With telephone
calls, dialing is normally completed before encryption
is enabled.
Encryption can be used with Multi-Net, LTR, and
conventional operation. Each group can be
programmed for encryption and then when that group
is selected, encryption is automatically enabled. The
user can also manually turn encryption on and off. The
encryption mode is indicated in the display or by a
front-panel indicator.
NOTE: Encryption is not compatible with compand-
ing; therefore, those features cannot be used together.
An OTAR (Over-The-Air-Reprogramming)
system is available which allows the system operator
to periodically change part of the encryption code and
certain other parameters. This system uses a specially-
equipped mobile transceiver, modem, IBM® PC or
compatible computer, and special OTAR software.
™
Continuous Sync is a trademark of Transcrypt International
Содержание Summit DM 975x
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Страница 131: ...SERVICING 7 8 Revised January 1995 Part No 001 9750 003 ...
Страница 156: ...9 19 Revised December 2000 Part No 001 9750 007 TRANSCEIVER EXPLODED VIEW PART 1 ...
Страница 157: ...Revised January 1995 Part No 001 9750 003 9 20 TRANSCEIVER EXPLODED VIEW PART 2 Remote Control Parts ...
Страница 168: ...Revised January 1995 Part No 001 9750 003 10 11 INTERCONNECT SCHEMATIC ...
Страница 169: ...Revised January 1995 Part No 001 9750 003 10 12 DISPLAY BOARD SCHEMATIC ...
Страница 170: ...Revised January 1995 Part No 001 9750 003 10 13 DISPLAY BOARD TOP VIEW DISPLAY BOARD BOTTOM VIEW ...
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Страница 183: ...Revised January 1995 Part No 001 9750 003 10 26 AUDIO LOGIC BOARD SCHEMATIC PART 1 OF 2 ...
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Страница 185: ...Revised January 1995 Part No 001 9750 003 10 28 AUDIO LOGIC BOARD LAYOUT TOP VIEW ...
Страница 186: ...Revised January 1995 Part No 001 9750 003 10 29 AUDIO LOGIC BOARD LAYOUT BOTTOM VIEW ...
Страница 188: ...Revised January 1995 Part No 001 9750 003 10 31 REMOTE TRANSCEIVER INTERCONNECT SCHEMATIC ...
Страница 189: ...Revised January 1995 Part No 001 9750 003 10 32 REMOTE CONTROL UNIT INTERFACE BOARD SCHEMATIC ...
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