Guardian G25AMK005, Technical Manual

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5-4 G U A R D I A N V H F M O B I L E
5.2.2.3 Audible Tones
The radio has several audible tones that are activated by states of operation or by radio faults. These tones are
described in Chapter 9.
5.2.3 Connectors
5.2.3.1 Accessory Connector
The accessory connector is a DB25 connector located on the rear panel of the radio. This connector is used for
multiple functions, including PC programming, keyfill, cloning, external speaker, and audio accessory attachment.
The pin names and functions are defined in Chapter 10.
5.2.3.2 Antenna Connector
The antenna connector is a SO239 jack.
5.2.3.3 DC Power Connector
The dc power connector is a 9-pin D connector in the rear panel of the radio.
5.3 Transceiver Characteristics
The radio frequency range is 136 to 174 MHz with channel spacing of 12.5 or 25 kHz, tunable in 5 kHz steps.
5.3.1 Transmitter Characteristics
5.3.1.1 Transmitter Output
The transmitter output consists of a single channel FM carrier using either conventional 12.5 or 25 kHz FM
modulation, or 12.5 kHz compatible 4-level FM (C4FM). The signal source is analog or digitized voice signals.
5.3.1.2 Transmit Squelch
Transmit squelch parameters are required to enable selective squelch communications options. These parameters
are described below.
5.3.1.2.1 Analog Transmit Squelch
There are 3 types of analog transmit squelch:
Type Description
None No squelch is included with the analog transmit signal
CTCSS Sub-audible CTCSS squelch tones are included with the analog transmit signal
DCS DCS variables are superimposed on the analog transmit signal
5.3.1.2.2 Digital Transmit Squelch
There are 4 types of digital transmit squelch:
Type Description
None No squelch is included with the digital transmit signal
Network Access
Code (NAC) A digital NAC is transmitted with the Project 25 digital transmit signal. The
primary purpose of this code is to allow the user access to a repeater network
TGID A digital TGID is transmitted with the Project 25 digital transmit signal. The
primary purpose of this selective digital calling identification is to group users into
functional teams