G U A R D I A N V H F 1 1 0 W M O B I L E
5-5
Type
Description
Individual Call
TGID is automatically set to 0000 (hex) and the user ID of the targeted radio is
activated within the Project 25 digital transmit signal
5.3.2 Receiver
Characteristics
5.3.2.1 Receiver
Performance
The receiver is capable of demodulating a single-channel FM carrier using either conventional 12.5 kHz FM, 25 kHz
FM, C4FM, or compatible quadrature phase shift keying (CQPSK) modulation. The receiver demodulates analog or
digital voice and data signals. The radio circuitry receives clear messages while operating in secure mode, and
secure messages while in the clear mode, if encryption is enabled.
5.3.2.2 Receive
Squelch
5.3.2.2.1 Analog Receive Squelch
There are 3 types of analog receive squelch:
Type
Description
Carrier (noise)
Squelch is opened on any intelligible analog signal
CTCSS
Squelch is opened on any analog signal having the correct CTCSS tone
DCS
Squelch is opened on any analog signal having the correct DCS variable
5.3.2.2.2 Digital Receive Squelch
There are 4 types of digital receive squelch:
Type
Description
Monitor
Squelch is opened on any intelligible digital signal. The NAC and talkgroup ID do not
have to match
Normal
Squelch is opened on any digital signal having the correct NAC
Selective
Squelch is opened on any digital signal having the correct NAC and TGID
Individual call Squelch is opened on a digital signal having a TGID of 0000 (hex) and a user ID matching
that of the receiving radio
5.4 Communication Security
The radio is capable of secure communication by means of type-3, software-based encryption, and is fully
compatible with any radio using Project 25 DES encryption. When the radio is operating in the secure mode, the
transmission of all tone squelch signals is disabled.
5.4.1 Algorithms
The radio is capable of single-bit cipher feedback (SBCF) DES (compatible with other manufacturers) 25 kHz
channels.
5.4.2 Keyfill
Keyfill is accomplished through the radio accessory connector using the PC programmer. The PC programming
cable is used to load the keys. The radio can store up to 16 encryption keys. The radio retains encryption keys until
they are rewritten or zeroized.
Summary of Contents for G25AMK005
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