Uniden BC796D APC0 25 manual Trunked Scanning, Motorola Trunking

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Trunked Scanning

While conventional scanning worked great while there were only a few groups wanting to use the frequencies, with the advent of smaller, lower-cost radios more and more agencies and businesses wanted to take advantage of the utility of 2-way radio. As a result, the bands that were used most became full, so new users were not able to take advantage of the technology as quickly as they wanted.

Trunking solved this frequency shortage by allowing multiple groups to use the same set of frequencies in a very efficient way. While each type of trunking system operates a little differently (see the next few sections), they all work on the same basic premise: even in a system with a lot of users, only a few users are ever transmitting at any one time.

Instead of being assigned a frequency, as with conventional systems, each group is assigned a Talkgroup ID. A central computer controls the frequency each group operates on...and this frequency selection is made each time a user transmits. So, while on a conventional system queries, replies, and follow-ups are all on a single frequency, they could each be on completely different frequencies on a trunked system. This semi-random frequency assignment made monitoring such a system impossible prior to Uniden’s invention of the Trunktracking scanner.

Motorola Trunking

While there are 4 different types of Motorola trunking systems, they all use the same basic trunking method. The system consists of one control channel plus one or more voice channels (typically 10, 20, or 30 total channels). When a user presses Push To Talk (PTT) to transmit, their radio first sends their talkgroup information to the control channel. The computer then assigns that talkgroup to a specific voice channel and transmits that data over the control channel. All radios in that talkgroup switch over to the assigned voice channel and the user can begin speaking. This all typically takes place in about a second...the person transmitting hears a beep from their radio when the channel is assigned and it is OK to start talking.

The four systems in use are:

•Motorola Type I – the radios send the radio ID, the fleet and subfleet talkgroup ID to the control channel each time they transmit. To program a Type I system, you need to know the system’s fleet map. The most common fleet maps are included at the back of this manual. You can also find fleet map resources on the web.

•Motorola Type II – the radios only send the radio ID and radio channel code to the control channel. The central computer keeps a database of radio ID’s and which talkgroup is assigned to which channel code for each radio, so with this system the user’s radio sends only about 1/3 the data as a Type I system with each transmission. Type II systems do not use Fleet-subfleet talkgroups; instead they use a 5-digit ID for each talkgroup.

•Type IIi Hybrid — these systems support a mix of both Type I and Type II users. Like Type I systems, you must know the system’s fleetmap to ensure proper tracking.

•Motorola Astro Digital — for channel control purposes, this type of system operates just like a Type II system — although the control channel can be a 3600 bps data rate (for mixed analog/digital systems) or a 9600 bps (for digital-only systems). Pure digital sys- tems can be implemented under APCO 25 Phase 1 or Phase 2 standards. Your BC796D is able to decode all unencrypted digitized voice traffic on either mixed mode or digital-only APCO 25 Phase 1 systems.

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Contents Page Page Contents Programming Trunked Systems General Use Location Cleaning Repairs Birdies Page FCC Wants You To Know Scanning Legally Introduction Page Using this Manual Conventional Scanning Understanding ScanningSimplex Operation Repeater OperationMotorola Trunking Trunked ScanningEdacs Trunking LTR Trunking Understanding Banks and ChannelsGetting More Information BC796D Front and Rear ViewIcon Description Display IconsIncluded With Your Scanner Connecting an Antenna Setting Up Your ScannerMounting an Antenna Optional AntennaMounting the Scanner in Your Vehicle Typical Mounting MethodsApplying Power for Vehicle Installation Applying Power Using Standard AC Power Desktop InstallationConnecting an External Speaker Connecting an EarphoneConnecting the Tape Recorder Connecting the Clone CableListening Safely RememberBasic Operation Setting the SquelchTurning On the Scanner Manually Selecting a Channel Using the MenuScanning Programmed Channels Locking/Unlocking BanksRestoring All Locked Out Channels Locking/Unlocking ChannelsPriority Scanning Priority Plus ScanningControlling How Much Information Appears Dimmer Light SettingTurning the Key Beep On/Off Locking the Enter keyDisabling the APCO25 Card Setting Squelch ModeMuting All Audio Trunk Scanning OptionsMonitoring Talkgroup ID’s Scanning Only Stored Talkgroups ID ScanSelecting Talkgroup Lists to Scan Holding on a Single TalkgroupUnlocking All Talkgroups Edacs BlockoutEdacs Patch Tracking Setting Data Skip Setting Chain SearchSearching Holding on an Active FrequencyAutomatically Storing Frequencies Storing Found FrequenciesSetting Delay for All Search Ranges Setting Subaudible Tones for SearchingSearching for Subaudible Tones Attenuating All Search RangesSearching for Trunk Systems Setting a Search RangePage Service Search Skip Service SearchUsing Weather Alert Same Using Weather Search and Weather Alert SameSearching for a Weather Broadcast Testing the Weather Alert Programming Bank Information Bank ConfigurationAssigning Bank Names Deleting Frequencies from Channels General ProgrammingTransferring Channel Information Entering Alpha InformationPage Select a Channel to Program Programming Conventional ChannelsEnter the Frequency Assigning a Text TagSetting the Subaudible Tone Option Setting the DelaySetting the Attenuator Setting Beep AlertChanging the Frequency Step Setting Priority Channels Setting the Modulation ModeProgramming Trunked Systems Using I-Call Motorola and Edacs only Setting Trunking DelayTurning I-Call On and Off for ID Search Multi-Track Setting Priority Talkgroups Motorola and Edacs onlyTurning I-Call On for ID Scan Multi-Track Operational DetailsPage Programming Motorola Systems Using Control Channel ProgrammingProgramming Type 2/Digital 800 and 900 MHz Systems Programming Type2/Digital VHF and UHF Systems Programming Type I and IIi Hybrid Systems Toggling End Code Detect Toggling the Status BitProgramming Edacs Systems Setting Edacs Emergency AlertProgramming Edacs Channels Setting Edacs Decimal Mode Programming Apco 25 Systems Setting Apco 25 Sound QualityProgramming LTR Systems Storing Known Talkgroups Programming TalkgroupsStoring Found Talkgroups Adding a Text Tag to an ID List Deleting Stored Talkgroup ID’sSeeing Talkgroup Activity PC Control Mode Using the Remote InterfaceCloning Scanner Settings Clone Master Unit Slave Unit Care and Maintenance Troubleshooting Problem Suggestion Specifications Glossary of Terms Page Page Appendix Preset Fleet MapsPreset Map Block Type I Programming Information User Defined Fleet MapsSize Code Restrictions Fleet Map Size CodesNWR-SAME Event Code SVS Severe WX Reverse List BC796D Flow Charts Scan Option Conventional System Option Dimmer Uniden America Corporation One Year Limited WarrantyMemo Memo Memo
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