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
Summary of Contents for Summit DM 975x
Page 105: ...MULTI NET SYSTEM OVERVIEW 5 10 Revised February 1997 Part No 001 9750 005 ...
Page 108: ...CIRCUIT DESCRIPTION 6 3 August 1993 Part No 001 9750 001 Figure 6 1 Transceiver Block Diagram ...
Page 123: ...CIRCUIT DESCRIPTION 6 18 August 1993 Part No 001 9750 001 ...
Page 131: ...SERVICING 7 8 Revised January 1995 Part No 001 9750 003 ...
Page 156: ...9 19 Revised December 2000 Part No 001 9750 007 TRANSCEIVER EXPLODED VIEW PART 1 ...
Page 168: ...Revised January 1995 Part No 001 9750 003 10 11 INTERCONNECT SCHEMATIC ...
Page 169: ...Revised January 1995 Part No 001 9750 003 10 12 DISPLAY BOARD SCHEMATIC ...
Page 171: ...Revised January 1995 Part No 001 9750 003 10 14 RF BOARD SCHEMATIC REVISED 800 MHZ ...
Page 172: ...Revised January 1995 Part No 001 9750 003 10 15 RF BOARD BOARD LAYOUT ALL 800 900 MHZ ...
Page 173: ...Revised January 1995 Part No 001 9750 003 10 16 RF BOARD BOARD SCHEMATIC 900 MHZ ...
Page 174: ...Revised January 1995 Part No 001 9750 003 10 17 RF BOARD BOARD SCHEMATIC UNREVISED 800 MHZ ...
Page 178: ...Revised January 1995 Part No 001 9750 003 10 21 PA BOARD SCHEMATIC 900 MHZ 30W ...
Page 179: ...Revised January 1995 Part No 001 9750 003 10 22 PA BOARD SCHEMATIC 900 MHZ 15W ...
Page 181: ...Revised January 1995 Part No 001 9750 003 10 24 PA BOARD SCHEMATIC UNREVISED 800 MHZ 35W ...
Page 182: ...Revised January 1995 Part No 001 9750 003 10 25 PA BOARD SCHEMATIC UNREVISED 800 MHZ 15W ...
Page 183: ...Revised January 1995 Part No 001 9750 003 10 26 AUDIO LOGIC BOARD SCHEMATIC PART 1 OF 2 ...
Page 184: ...Revised January 1995 Part No 001 9750 003 10 27 AUDIO LOGIC BOARD SCHEMATIC PART 2 OF 2 ...
Page 185: ...Revised January 1995 Part No 001 9750 003 10 28 AUDIO LOGIC BOARD LAYOUT TOP VIEW ...
Page 186: ...Revised January 1995 Part No 001 9750 003 10 29 AUDIO LOGIC BOARD LAYOUT BOTTOM VIEW ...
Page 188: ...Revised January 1995 Part No 001 9750 003 10 31 REMOTE TRANSCEIVER INTERCONNECT SCHEMATIC ...
Page 189: ...Revised January 1995 Part No 001 9750 003 10 32 REMOTE CONTROL UNIT INTERFACE BOARD SCHEMATIC ...
Page 216: ...Part Number 001 9750 007 12 00 hph Printed in U S A ...
