Nortel Networks RTU-292 Front Panel Buttons and Indicators, Main Board, Audio BUS Arrangement

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RTU-292 Operations Manual

4 RTU-292 Theory Of Operation

4.1 GENERAL

This section gives enough detail of the theory of operation of the RTU-292 audio and power supply sections to allow them to be troubleshot in the field. The same level of detail is not supplied for the DSP module and the CPU portion as they are considered impractical to field troubleshoot because of the specialized knowledge and test equipment required. If a fault is suspected in these sections, factory repair is required.

4.2 FRONT PANEL BUTTONS AND INDICATORS

Figure 8-1 is a schematic of the RTU-292 front panel. The control pushbuttons and associated LEDs are arranged in three separate PC board assemblies: the Tel Line Switch Assembly, the Handset Switch Assembly, and the Speaker Switch Assembly. Signals from each of these assemblies are combined into one ribbon cable that plugs into the Main Board at J3. Each control pushbutton switches +5V onto its control line when ON and open circuit when OFF. Pulldown resistors on each of the control inputs pull the line to ground when its button is OFF. The buttons are read by the processor on the Main Board. The processor, not the pushbuttons, controls the unit’s audio gates as well as the front panel LEDs.

4.3 MAIN BOARD

Main Board Circuitry is detailed in Figure 8-2.

4.3.1 AUDIO BUS ARRANGEMENT

The audio switching is bus oriented. Each major bus is named after the output signal that it carries for distribution with the major buses as follows:

Signal
Name	Source	Comment
TEL	U8C-11	Telephone Receive Signal.
MIC	U15B-7	Amplified/AGC’d Microphone Signal.
RXA	U22D-6	Amplified Radio Receiver Signal.
RING	U33A-2	Telephone Ringer Signal.
DTMF	J13-32	DTMF Dialer Output.

The bus signals are each gain-leveled to a nominal 0 dBm (0.775V rms) average amplitude, except for the hybrid in/out signals, which are usually at a –12 dBm (0.194V rms). The bus signals are routed to various destinations through analog gates controlled by signals from the CPU on the Main Board.

4-19	JPS Communications, Inc.

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Contents JPS P/N Revision July JPS Communications, IncPhone 919 Fax 919 Proprietary StatementTable of Contents RTU-292 Theory of Operation Front Panel Buttons and Indicators Schematic Diagrams List Of Figures List of Tables Glossary This page intentionally left blank General Scope DescriptionTelephone Interface AssembliesMain Board DSP Module Power Supply SectionHandset/Speaker Interface Radio InterfaceQty Part Number Equipment and Accessories SuppliedOptional Equipment Not Supplied OptionsRTU-292 Specifications Reshipment of Equipment GeneralUnpacking and Inspection FCC Part 68 Regulations Installation OverviewInstallation Considerations Feature / Function Adjustment Default Setting 1RTU-292 Factory Default SettingsLine Voltage Selection Power RequirementsInput Power Selection DC Input Power SelectionSetting Telephone Send and Receive Levels Configuring the RTU-292Programming Mode Setup Parameters Telephone Send/Receive Levels Recommended Phone Line SettingsFactory default settings are indicated by an asterisk Type of SystemVOX Sensitivity VOX HangtimeVOX Hangtime VOX SensitivityRX Line Input Impedance Dial ModeDial Mode Telephone Ring VolumeSW2-8 Full/Half Duplex Off Full Duplex Radio Control ModeSW1-3 Radio Control Off Disabled Enabled Full/Half DuplexVoice Prompts Password Protection10Password Protection 11Voice Prompts Enable13 Local Phone Ringthrough 12Local Phone Enable14TX Level Set-up Mode Interconnect InformationRadio Connection Telephone Connection15J1 TEL Line RJ-11C Pin Function17J7 Handset RJ12C Jack Handset Connector16P1-RADIO DB-9 Male 18Terminal Block 6 Position Terminal Block5 RS-232 Connection Audio Level Setup and Adjustments19P2 RS-232 Connector DB-9 Male Setting the Transmit Level10.1.2 Setting the Receive LevelRTU-292 Operations Manual Outline Dimensions Control and Connector Locations Location Of Internal Option Settings Internal Option Setting Details Audio Interface Wiring Diagram Interface Details Installation Checklist Installation ChecklistOptions Installation and Configuration Front Panel CONTROLS, Indicators and Connectors TEL Line Buttons Speaker Volume ControlPhones Volume Control KeypadKEY Pushbutton Speaker ButtonsAuto ANS Button Audible Ring Button7 P1 AC Power Connector Rear Panel Connectors1 P1 Radio Connector 4 J2 Local Phone ConnectorPlacing a Telephone Call OperationOperation Overview USE of the RTU-292 Speaker to Monitor AudioPutting a Telephone Call on Hold Using the Handset with the RadioConnecting the Radio to the Telephone Line Receiving a Telephone Call8.2 Manual Phone Patch Procedure8.1 8.6 8.38.4 8.5Automated Operation Negative Acknowledge ErrorRemote KEY Self TestRadio Is Unkeyed Unkeyed Disconnecting DisconnectWaiting For Input Query Radio Is Keyed KeyedRTU-292 Adapts To The Phone Line Caller Enters The Password if enabledCaller Dials The RTU-292 Terminating a Call RTU-292 Enters the Command ModePlacing a Call in the Command Mode Operating the RTU-292 from the Front Panel Keypad Dtmf Control CommandsDtmf Command Function 1Standard Dtmf Operational Commands2Programming Mode Dtmf Commands Calling Timer RTU-292 Password ProtectionInactivity Disconnect Timer Programming the Speed Dial Directory Using the RTU-292 Speed Dial FeatureUsing the Speed Dial Feature Optional 4 Wire Operation Factory ResetSpeed Dial Reset Audio BUS Arrangement Front Panel Buttons and IndicatorsMain Board Telephone Receive Circuits Telephone Interface CircuitsTelephone Send Circuits Transmitter Audio Output Ring Detector and Tone RingerRadio Interface Circuits Receiver Input AmplifierSpeaker and Headphone Circuits Dtmf DetectorFSK Modem Microphone CircuitPeak Detector Audio DelayAdaptive Hybrid Noise Generator8 CPU Power SupplyAC Power Supply DC Power SupplySpeech Processor Option Interface BoardVoice Prompt Option Prompt Tone GeneratorDIAL/BUSY Generators Local Phone OptionVoice Prompt Software Interface CircuitryCommands Sent to the RTU-292 RS-232 Remote Control Overview1Command Summary Audible Ring Command Null CommandAuto Answer Command Dial Command Date CommandDtmf Command Disconnect CommandHandset Radio Command Handset Phone CommandSpeaker Radio Command Speaker Phone CommandSD nnALL num.? CR Speed Dial CommandTel-Line Radio Command Tel-Line Phone CommandSoftware Version Command Time CommandResponse Summary Status Returned from the RTU-292Call Starting Response Null ResponseAuto Answer Response Dtmf Response Dial ResponseDisconnect Response Handset Radio Response Elapsed Time ResponseHandset Phone Response Speaker Radio Response Speaker Phone ResponseTel-Line Radio Response Speed Dial ResponseTel-Line Phone Response Version Response Time/Date ResponseCall Progress Responses Response Error CodesResponse Error Codes Call Progress Responses from the RTU-292Alignment Preventive MaintenanceRepair or Replacement Performance TestingHybrid Balance Measurement Hybrid Balance Test Set-Up Main Hybrid Test Procedure Alternate Hybrid Test Procedure VOX Sensitivity Measurement VOX Sensitivity Test Set-Up VOX Test ProcedureFault Analysis Description Replaceable Parts ListDescription Reference Designator RTU-292 Operations Manual Reference Designator RTU-292 Options Special Software VersionsOperation Installation and ConfigurationVoice Prompts Enable SW1-6 Voice Prompts Off Disabled EnabledVoice Prompt Option Installation SW1-8 Ringthrough Off Disabled Enabled Local Phone Option Installation and ConfigurationLocal Phone Enable SW1-7 Local Phone Off Disabled EnabledLocal Phone Option Operation 5Local Phone Dtmf CommandsVMM-100 Analog Interface VMM-100 HardwareVMM-100 DSP Section Noise Reduction Algorithm VMM-100 Installation and ConfigurationVMM-100 Software VMR AlgorithmVMM-100 Option Installation Environmental VMM-100 SpecificationsVMM-100 Switch Functions VMM-100 I/O Connector Information P9Dtmf Access Option After the Call Begins RTU-292 Prompts for Confirmation Squelch Break Access OptionChecking The Time And Date Setting The TimeSetting The Date Call Logging OptionControlling the Radio VIA the RTU-292 Front Panel Keypad Radio Control OptionCommand Followed By Command Description 9DTMF Radio Control CommandsSchematic Diagrams Blank Index Environmental Self Test Speech Processor