Dual Radio Operation (Keystone Concept)

A Dual Radio configuration allows two APX™ Mobile radios to operate together with a single APX™ Control Head. The two radios can be either the 7500 model radios, 6500 model radios or the 8500 model radios, and the single Control Head must be an O7 Control Head. This unique configuration allows for different combinations of simultaneous Rx audio, simultaneous Tx audio and data, and simultaneous receive and transmit of audio and data. This feature Includes high-power or mid-power radios, and both single-band and dual-band radios.

The Dual Radio configuration is Phase 2 Voice Capable - TDMA.

The sum of both radio's frequency bands within a Dual Radio configuration are considered as either "In-Band" or "Cross-Band".

Dual radios are considered to be "in-band" when at least one frequency band of one radio overlaps with any one band of the other radio (single band or dual band). Dual radios are considered to be "cross-band" when entirely different frequency bands exist for the two radios (single band or dual band). This is based on each radio's available frequency band(s) (Primary Frequency Band and Secondary Frequency Band), regardless of the frequencies being used in each radio's codeplug.

A “Cross Band” scenario is capable of many more communication advantages than an “In Band” scenario.

METHODS:	TYPES:	EXAMPLES:	CROSS-BAND	IN-BAND
Simultaneous Rx	Voice	Receive audio on both radios at the same time	Yes	Yes
Simultaneous Tx	Voice	Press PTT and have both radios transmit	No	No
	Data	Both radios transmit GPS data	Yes	No
	Voice & Data	When pressing PTT on the selected radio to transmit voice, the unselected radio can transmit GPS data	Yes	No
Simultaneous Rx & Tx	Voice	When pressing PTT on the selected radio to transmit voice, and the unselected radio can receive audio and unmute its speaker ( see Cross Band Mute "Disabled" )	Configurable	No
	Data	When the one radio is receiving OTAR, the other radio can transmit OTAR request	Yes	No
	Voice & Data	When one radio is receiving voice, the other radio can transmit GPS data	Yes	No
	Voice & Data	When pressing PTT on the selected radio to transmit voice, the unselected radio can receive OTAR	Yes	No

	The control head uses unique icons to reflect which radio is currently selected, and which radio is receiving audio. This allows the radio-user to more easily decide how to respond to incoming calls.
	If the unselected radio is transmitting, the transmit indicator does appear in the radio's display.

1.	In a Dual Radio configuration ... The two radios (or bricks) must be programmed separately due to system reset during the codeplug and firmware updating. The two radios must have matching firmware versions. The two radios must use the same Radio Display Language. The following features are mutually exclusive with Dual Radio: Multi Control Head, DVRS, Consolette, Remote Site Interface, and RF Modem. When one radio is inhibited, the other radio becomes inhibited; conversely, when one radio is uninhibited, the other radio becomes uninhibited. Since simultaneous Voice transmissions from both radios is not possible, remote monitor is only allowed on one of the radios at any given time; in other words, when one radio is transmitting voice (either via a PTT button-press, or Emergency Auto Transmit, or due to remote-monitoring), the other radio cannot be remote-monitored.
2.	One radio is defined as the "Primary Radio" and the other radio must be programmed as the "Secondary Radio". Dual Radio features must be defined on the "Primary Radio", or the "Secondary Radio", or sometimes on both radios. The Radio Selection field chooses either "Primary" or the "Secondary" to be designated for each radio's codeplug. The Emergency Radio field selects which radio handles Emergency Mode operation, however is only programmed on the "Primary" radio. Click to see Warnings for "Emergency Evacuation Tone" and "Emergency Silent Alarm". The Talkgroup Mute Option is only programmed on the "Secondary" radio. The Enable Secondary Radio Tx is only programmed on the "Secondary" radio. The Cross Band Mute Option is programmed on the "Primary" radio and the "Secondary" radio. The Fixed Swap Menu is programmed on the "Primary" radio and the "Secondary" radio. The Radio Swap button-press and / or Radio Swap menu selection allows the radio-user to switch between the "Primary" and "Secondary" and must be programmed on both radios. A unique Radio Alias should be defined for each radio. When the radio is radio-user "Swapped", the selected radio's Alias appears momentarily in the Control Head's display, and Intelligent Lighting also differentiates the Primary radio from the Secondary radio.
3.	*The following features are configured on the "Primary" radio only:* All VIP Out pins. The PA / Siren and the Universal Relay Controller features; additionally, the hardware devices for these features must be connected to the "Primary" radio. The GunLock, Horn and Lights, and Aux Control features, and their corresponding VIP Out pins. The Save Day Night Mode feature. The Radio Lock feature (if the "Primary" radio is locked, then both radios are locked). The "Primary" radio arbitrates power-up and power-off for both radios through its Ignition Switch and Ignition Auto Power Off selections. However, button-press or menu-selections related to all of the above Radio Wide features (and also Dim) are programmable for both the "Primary" and the "Secondary" radios, and must be configured the same for both radios. In this way, the radio-user may seamlessly operate these features regardless of the current radio selection, and swapping the selected radio does not change the current state of these features.
4.	When programming any button selections or menu-item selections, in order to avoid radio-user confusion and to promote seamless operation, it is strongly recommended to configure all of the button selections the same on both radios.

The Dual Radio Feature

(Learning and Programming Radio Features)

	Due to potential frequency band overlap, the combination of "UHF1" and "UHF2" on dual radios is considered "in-band".
	When the radios are "in-band", due to potential RF interference, the functionality of one of the radios is limited when the other radio is transmitting.