System Feature Overview 15
• Scan (normal and priority)
• Battery saver
2.When operating in Digital Direct Mode, MOTOTRBO uses one physical channel
configured for a 12.5 kHz channel bandwidth. On that one direct 12.5 kHz physical
channel bandwidth, a MOTOTRBO digital system can support only one voice (or data)
path at a time. Without a repeater in place to coordinate the time slot sequence among
radios, only one radio can transmit at a time in order to guarantee transmissions do not
overlap.
In repeater-based radio communications systems, a voice path requires a pair of channels: one for
transmission, the other for reception.
2.2.1.1 Analog Repeater Mode
When operating in Analog Repeater Mode, MOTOTRBO operates similar to existing analog
repeaters by supporting one voice path (transmit and receive) on one pair of physical channels,
and can be configured to operate in 12.5/25 kHz channel bandwidth systems.
2.2.1.2 Digital Repeater Mode
When operating in Digital Repeater Mode, MOTOTRBO uses a pair of physical channels
configured for 12.5 kHz channel bandwidth. Through the use of Time Division Multiple Access
(TDMA) technology and the synchronization provided by the repeater, MOTOTRBO splits each
12.5 kHz channel (one transmit and one receive) into two independent time slots or logical
channels within the 12.5 kHz physical channel bandwidth. This allows the user to assign voice or
data traffic to either of the time slots independently. To the end user, this means they now have two
voice or data channels that can be managed independently, instead of one. These two logical
channels (two time slots) can transmit and receive independently of each other. The two logical
channels in a 12.5 kHz channel makes the channel equivalent to a 6.25 kHz wide channel.
2.2.1.3 Dynamic Mixed Mode
When operating in Dynamic Mixed Mode (DMM), MOTOTRBO uses a pair of physical channels
configured for 12.5 kHz channel bandwidth for digital operation and 25 kHz and/or 12.5 kHz
channel bandwidth for analog operation. The repeater dynamically switches between analog and
digital modes based on the call it receives from radios. If an analog radio transmits, the repeater
switches to analog mode to repeat the analog call. However, the repeater only repeats analog calls
that are qualified by PL (DPL/TPL). If a digital radio transmits, then the repeater switches to digital
mode to repeat the digital call if the call uses the right color code. While the repeater repeats one
analog call at a time, it can repeat 2 digital calls at a time, one on each logical channel.
When a repeater repeats a new digital call that starts on one of the logical channels, the repeater
does not qualify any analog call including an Emergency Call until the digital call (both the
transmission and call hang time) is over and the corresponding channel hang time has expired.
Upon the expiry of channel hang time, only then does the repeater start qualifying both analog and
digital calls simultaneously. Similarly, if an analog call is being repeated, the repeater does not
qualify any digital call including digital data and Emergency Calls on any of the two logical
channels until the analog call is over and the corresponding hang time has expired.
Analog console device(s) are supported only when the repeater has not qualified an OTA digital
call. If an analog console device tries to key up the repeater when a digital call has been received
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