JPS RTU-292C User manual

1
Installation and Operation Manual
RTU-292C
RADIO / TELEPHONE
INTERFACE UNIT
Designed and Manufactured by:
JPS Interoperability Solutions, Inc.
jpsinterop.com
5800 Departure Drive
Raleigh, NC 27616
phone: [phone]
email: [email protected] / [email protected]
This Manual is P/N 5020-500200 Revision 4 June 2018

RTU-292C Operations Manual
2
FEDERAL COMMUNICATIONS COMMISSION
(FCC) COMPLIANCE NOTICE:
RADIO FREQUENCY INTERFERENCE NOTICE
This equipment has been tested and found to comply with the limits for a Class
A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed
to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, maycause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to
cause harmful interference in which case users will be required to correct the
interference at their own expense.
CAUTION
Changes or modifications to this equipment not expressly approved by JPS
Interoperability Solutions could void the user’s authority to operate this
equipment.
NOTICE
JPS Interoperability Solutions reserves the right to make changes to the
equipment and specifications without prior notice.
PROPRIETARY STATEMENT
The information contained in this manual is the property of JPS Interoperability
Solutions and is intended for the purchaser’s use only. It may not be reproduced
without the expressed written consent of JPS Interoperability Solutions, Inc.
© 2018 JPS Interoperability Solutions, Inc.

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3
Content Table Sample
(Hazardous substances present)
部件名称
(Parts)
有毒有害物质或元素 (Hazardous Substance)
铅
(Pb)
汞
(Hg)
镉
(Cd)
六价铬
(Cr6+)
多溴联苯
(PBB)
多溴二苯醚
(PBDE)
金属部件
(Metal Parts)
X
○
○
X
○
○
电路模块
(Circuit Modules)
X
○
○
○
○
○
电缆及电缆组件
(Cables & Cable Assemblies)
×
○
○
×
○
○
塑料和聚合物部件
(Plastic and Polymeric parts)
○
○
○
○
○
○
○： 表示该有毒有害物质在该部件所有均质材料中的含量均在SJ/T11363-2006 标准规定的限量要求以下。
Indicates that the concentration of the hazardous substance in all homogeneous materials in the parts is
below the relevant threshold of the SJ/T 11363-2006 standard.
×： 表示该有毒有害物质至少在该部件的某一均质材料中的含量超出SJ/T11363-2006 标准规定的限量要求。
Indicates that the concentration of the hazardous substance of at least one of all homogeneous
materials in the parts is above the relevant threshold of the SJ/T 11363-2006 standard.
注意:在所售产品中可能会也可能不会含有所有所列的部件。
Note: that some of the component types listed above may or may not be a part of the enclosed product.
除非另外特别的标注,此标志为针对所涉及产品的环保使用期标志.
某些可更换的零部件可能会有一个不同的环保使用期标志贴在其产品上.
此环保使用期限只适用于在用户手册所规定条件下工作的产品.
The Environmentally Friendly Use Period (EFUP) for all enclosed products and their parts
are per the symbol shown here, unless otherwise marked. Certain field-replaceable parts
may have a different EFUP and so are marked to reflect such. The Environmentally
Friendly Use Period is valid only when the product is operated under the conditions
defined in the user manual.
10

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Table of Contents
1GENERAL INFORMATION ......................................................................................................................1-1
1.1 SCOPE ....................................................................................................................................................1-1
1.2 DESCRIPTION.......................................................................................................................................1-1
1.2.1 GENERAL......................................................................................................................................1-1
1.3 ASSEMBLIES ........................................................................................................................................1-2
1.3.1 MAIN BOARD...............................................................................................................................1-2
1.3.2 FRONT PANEL SWITCH ASSEMBLIES ....................................................................................1-3
1.3.3 OPTIONS INTERFACE BOARD..................................................................................................1-3
1.3.4 OPTIONS........................................................................................................................................1-5
2INSTALLATION..........................................................................................................................................2-1
2.1 GENERAL..............................................................................................................................................2-1
2.2 UNPACKING AND INSPECTION .......................................................................................................2-1
2.3 RESHIPMENT OF EQUIPMENT..........................................................................................................2-1
2.4 INSTALLATION OVERVIEW .............................................................................................................2-2
2.5 INSTALLATION CONSIDERATIONS ................................................................................................2-3
2.5.1 FCC REGULATORY INFORMATION ........................................................................................2-3
2.5.2 TELEPHONE HEARING AID COMPATIBILITY.......................................................................2-3
2.6 POWER REQUIREMENTS...................................................................................................................2-5
2.7 POWER SELECTION............................................................................................................................2-5
2.7.1 LINE VOLTAGE SELECTION .....................................................................................................2-5
2.7.2 DC INPUT POWER SELECTION.................................................................................................2-5
2.7.3 FUSE INFORMATION..................................................................................................................2-5
2.8 CONFIGURING THE RTU-292C..........................................................................................................2-6
2.8.1 PROGRAMMING MODE SETUP PARAMETERS .....................................................................2-6
2.8.2 SETTING TELEPHONE SEND AND RECEIVE LEVELS..........................................................2-6
2.8.3 VOX HANGTIME..........................................................................................................................2-7
2.8.4 VOX SENSITIVITY.......................................................................................................................2-8
2.8.5 BALANCED/UNBALANCED RADIO INTERFACE ..................................................................2-8
2.8.6 RX LINE INPUT IMPEDANCE ....................................................................................................2-8
2.8.7 DIAL MODE ..................................................................................................................................2-9
2.8.8 TELEPHONE RING VOLUME.....................................................................................................2-9
2.8.9 FULL/HALF DUPLEX RADIO.....................................................................................................2-9
2.8.10 SERIAL PORT BAUD RATE........................................................................................................2-9
2.8.11 RADIO CONTROL MODE..........................................................................................................2-10
2.8.12 PASSWORD PROTECTION .......................................................................................................2-10
2.8.13 VOICE PROMPTS .......................................................................................................................2-10
2.8.14 LOCAL PHONE / LOCAL PHONE RING-THROUGH .............................................................2-11
2.8.15 TRANSMIT LEVEL SET-UP MODE..........................................................................................2-12
2.8.16 MISCELLANEOUS JUMPERS...................................................................................................2-12
2.9 INTERCONNECT INFORMATION ...................................................................................................2-12
2.9.1 TELEPHONE CONNECTION.....................................................................................................2-12
2.9.2 RADIO CONNECTION ...............................................................................................................2-13
2.9.3 HANDSET CONNECTOR...........................................................................................................2-13
2.9.4 RS-232 CONNECTION................................................................................................................2-14
2.10 AUDIO LEVEL SETUP AND ADJUSTMENTS ................................................................................2-14
2.10.1 SETTING THE TRANSMIT LEVEL ..........................................................................................2-14
2.10.2 SETTING THE RECEIVE LEVEL..............................................................................................2-15
2.11 INSTALLATION CHECKLIST...........................................................................................................2-23
2.12 OPTIONS INSTALLATION AND CONFIGURATION.....................................................................2-23

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3OPERATION.................................................................................................................................................3-1
3.1 GENERAL ..............................................................................................................................................3-1
3.2 FRONT PANEL CONTROLS, INDICATORS AND CONNECTORS.................................................3-1
3.2.1 MAIN POWER SWITCH...............................................................................................................3-1
3.2.2 HANDSET JACK ...........................................................................................................................3-1
3.2.3 HANDSET ......................................................................................................................................3-1
3.2.4 SPEAKER .......................................................................................................................................3-1
3.2.5 KEYPAD.........................................................................................................................................3-1
3.2.6 SPEAKER VOLUME CONTROL..................................................................................................3-2
3.2.7 PHONES VOLUME CONTROL....................................................................................................3-2
3.2.8 TEL LINE BUTTONS ....................................................................................................................3-2
3.2.9 HANDSET BUTTONS...................................................................................................................3-2
3.2.10 SPEAKER BUTTONS....................................................................................................................3-2
3.2.11 TEL VOX........................................................................................................................................3-3
3.2.12 AUTO ANS BUTTON....................................................................................................................3-3
3.2.13 AUDIBLE RING BUTTON............................................................................................................3-3
3.2.14 KEY PUSHBUTTON .....................................................................................................................3-3
3.2.15 PEAK LED......................................................................................................................................3-3
3.3 REAR PANEL CONNECTORS.............................................................................................................3-3
3.3.1 P1 RADIO CONNECTOR..............................................................................................................3-3
3.3.2 J1 TEL LINE...................................................................................................................................3-4
3.3.3 J2 LOCAL PHONE CONNECTOR................................................................................................3-4
3.3.4 P2 RS-232 CONNECTOR .............................................................................................................3-4
3.3.5 DC INPUT TERMINAL BLOCK...................................................................................................3-4
3.4 OPERATION ..........................................................................................................................................3-4
3.4.1 OPERATION OVERVIEW ............................................................................................................3-4
3.4.2 USE OF THE RTU-292C SPEAKER TO MONITOR AUDIO......................................................3-4
3.4.3 PLACING A TELEPHONE CALL.................................................................................................3-4
3.4.4 RECEIVING A TELEPHONE CALL ............................................................................................3-5
3.4.5 PUTTING A TELEPHONE CALL ON HOLD..............................................................................3-5
3.4.6 USING THE HANDSET WITH THE RADIO...............................................................................3-5
3.4.7 CONNECTING THE RADIO TO THE TELEPHONE LINE........................................................3-5
3.4.8 MANUAL PHONE PATCH PROCEDURE...................................................................................3-6
3.4.9 TRANSMITTER KEYING, HALF DUPLEX SYSTEM ...............................................................3-7
3.4.10 TRANSMITTER KEYING, FULL DUPLEX SYSTEM................................................................3-8
3.5 REMOTE KEY .......................................................................................................................................3-8
3.6 SELF TEST.............................................................................................................................................3-8
3.7 AUTOMATED OPERATION ................................................................................................................3-8
3.7.1 TONE PROMPTS...........................................................................................................................3-8
3.7.2 VOICE PROMPTS..........................................................................................................................3-9
3.7.3 CALLING THE RTU-292C VIA THE OUTSIDE LINE ...............................................................3-9
3.7.4 PLACING A CALL IN THE COMMAND MODE:.....................................................................3-11
3.7.5 TERMINATING A CALL:...........................................................................................................3-11
3.7.6 DTMF CONTROL COMMANDS................................................................................................3-12
3.7.7 RTU-292C PASSWORD PROTECTION.....................................................................................3-15
3.7.8 INACTIVITY DISCONNECT TIMER ........................................................................................3-15
3.7.9 CALLING TIMER........................................................................................................................3-15
3.7.10 USING THE RTU-292C SPEED DIAL FEATURE.....................................................................3-16
3.7.11 SPECIAL DIALING FEATURES ................................................................................................3-18
3.8 FACTORY RESET ...............................................................................................................................3-18
3.9 SPEED DIAL RESET ...........................................................................................................................3-18
4REMOTE CONTROL PROTOCOL ..........................................................................................................4-1
4.1 GENERAL ..............................................................................................................................................4-1
4.2 RS-232 REMOTE CONTROL OVERVIEW .........................................................................................4-1
4.3 COMMANDS SENT TO THE RTU-292C.............................................................................................4-1

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4.3.1 NULL Command ............................................................................................................................4-3
4.3.2 Auto Answer Command..................................................................................................................4-3
4.3.3 Audible Ring Command..................................................................................................................4-3
4.3.4 Date Command................................................................................................................................4-4
4.3.5 Dial Command ................................................................................................................................4-4
4.3.6 Disconnect Command .....................................................................................................................4-5
4.3.7 DTMF Command............................................................................................................................4-5
4.3.8 Handset Phone Command ...............................................................................................................4-6
4.3.9 Handset Radio Command................................................................................................................4-6
4.3.10 Speaker Phone Command ...............................................................................................................4-7
4.3.11 Speaker Radio Command................................................................................................................4-7
4.3.12 Speed Dial Command......................................................................................................................4-8
4.3.13 Tel-Line Phone Command ..............................................................................................................4-9
4.3.14 Tel-Line Radio Command...............................................................................................................4-9
4.3.15 Time Command.............................................................................................................................4-10
4.3.16 Software Version Command .........................................................................................................4-10
4.4 STATUS RETURNED FROM THE RTU-292C..................................................................................4-11
4.4.1 NULL Response............................................................................................................................4-12
4.4.2 Auto Answer Response.................................................................................................................4-12
4.4.3 Call Starting Response ..................................................................................................................4-12
4.4.4 Dial Response................................................................................................................................4-13
4.4.5 Disconnect Response.....................................................................................................................4-13
4.4.6 DTMF Response ...........................................................................................................................4-13
4.4.7 Elapsed Time Response ................................................................................................................4-14
4.4.8 Handset Phone Response ..............................................................................................................4-14
4.4.9 Handset Radio Response...............................................................................................................4-14
4.4.10 Speaker Phone Response...............................................................................................................4-15
4.4.11 Speaker Radio Response ...............................................................................................................4-15
4.4.12 Speed Dial Response.....................................................................................................................4-16
4.4.13 Tel-Line Phone Response..............................................................................................................4-16
4.4.14 Tel-Line Radio Response..............................................................................................................4-16
4.4.15 Time/Date Response .....................................................................................................................4-17
4.4.16 Version Response..........................................................................................................................4-17
4.5 CALL PROGRESS RESPONSES FROM THE RTU-292C................................................................4-18
4.6 RESPONSE ERROR CODES ..............................................................................................................4-18
5MAINTENANCE AND REPAIR ................................................................................................................5-1
5.1 GENERAL..............................................................................................................................................5-1
5.2 PREVENTIVE MAINTENANCE..........................................................................................................5-1
5.3 REPAIR OR REPLACEMENT..............................................................................................................5-1
5.3.1 GENERAL PRECAUTIONS AND NOTES ..................................................................................5-1
5.4 ALIGNMENT.........................................................................................................................................5-1
5.5 PERFORMANCE TESTING..................................................................................................................5-1
5.5.1 TEST EQUIPMENT REQUIRED..................................................................................................5-1
5.5.2 HYBRID BALANCE MEASUREMENT ......................................................................................5-2
5.5.3 VOX SENSITIVITY MEASUREMENT........................................................................................5-5
6RTU-292C OPTIONS...................................................................................................................................6-1
6.1 GENERAL..............................................................................................................................................6-1
6.1.1 Special Software Versions ..............................................................................................................6-1
6.2 VOICE PROMPT OPTION....................................................................................................................6-2
6.2.1 INSTALLATION AND CONFIGURATION ................................................................................6-2
6.2.2 OPERATION..................................................................................................................................6-2
6.3 DTMF ACCESS OPTION......................................................................................................................6-3
6.3.1 Initiate Call Via Attention Signal....................................................................................................6-4
6.3.2 RTU-292C Response to Attention Signal .......................................................................................6-4

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6.3.3 Radio Caller Provides Calling Directions........................................................................................6-4
6.3.4 RTU-292C Plays Back Phone Number & Prompts for Confirmation.............................................6-4
6.3.5 RTU-292C Places the Call ..............................................................................................................6-4
6.3.6 After the Call Begins.......................................................................................................................6-4
6.4 SQUELCH BREAK ACCESS OPTION.................................................................................................6-5
6.4.1 Initiate Call Via Attention Signal ....................................................................................................6-5
6.4.2 RTU-292C Response to Attention Signal........................................................................................6-5
6.4.3 RTU-292C Prompts for Confirmation.............................................................................................6-5
6.4.4 RTU-292C Places the Call ..............................................................................................................6-5
6.4.5 After the Call Begins.......................................................................................................................6-5
6.5 THE CALL LOGGING OPTION...........................................................................................................6-6
6.5.1 Checking The Time And Date.........................................................................................................6-6
6.5.2 Setting The Time.............................................................................................................................6-6
6.5.3 Setting The Date..............................................................................................................................6-6
6.5.4 Call Logging....................................................................................................................................6-6
6.6 RADIO CONTROL OPTION.................................................................................................................6-6
6.6.1 CONTROLLING THE RADIO VIA THE RTU-292C FRONT PANEL KEYPAD......................6-7
7INDEX............................................................................................................................................................7-1

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List Of Figures
FIGURE 2-1 OUTLINE DIMENSIONS ...................................................................................................................2-17
FIGURE 2-2 CONTROL AND CONNECTOR LOCATIONS .......................................................................................2-18
FIGURE 2-3 LOCATION OF INTERNAL OPTION SETTINGS...................................................................................2-19
FIGURE 2-4 INTERNAL OPTION SETTINGS DETAILS...........................................................................................2-20
FIGURE 2-5 AUDIO INTERFACE WIRING DIAGRAM ...........................................................................................2-21
FIGURE 2-6 INTERFACE DETAILS ......................................................................................................................2-22
FIGURE 5-1 HYBRID BALANCE TEST SET-UP......................................................................................................5-3
FIGURE 5-2 VOX SENSITIVITY TEST SET-UP......................................................................................................5-5
FIGURE 6-1 VOICE PROMPT OPTION INSTALLATION ...........................................................................................6-3

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List of Tables
FIGURE 2-1 OUTLINE DIMENSIONS....................................................................................................................2-17
FIGURE 2-2 CONTROL AND CONNECTOR LOCATIONS........................................................................................2-18
FIGURE 2-3 LOCATION OF INTERNAL OPTION SETTINGS ...................................................................................2-19
FIGURE 2-4 INTERNAL OPTION SETTINGS DETAILS...........................................................................................2-20
FIGURE 2-5 AUDIO INTERFACE WIRING DIAGRAM............................................................................................2-21
FIGURE 2-6 INTERFACE DETAILS.......................................................................................................................2-22
FIGURE 5-1 HYBRID BALANCE TEST SET-UP......................................................................................................5-3
FIGURE 5-2 VOX SENSITIVITY TEST SET-UP......................................................................................................5-5
FIGURE 6-1 VOICE PROMPT OPTION INSTALLATION ...........................................................................................6-3

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11
Glossary
Adaptation
The process whereby the RTU-292C DSP algorithms detect reflected signal information in a
connected line and tune the DSP hybrid for a broadband null with minimum reflection.
COR
Carrier Operated Relay - A receiver signal that gives a positive indication that a carrier or signal
is being received and that the receiver is unsquelched. Same as COS.
COS
Carrier Operated Squelch - See COR.
CTCSS
Continuous Tone Controlled Squelch System. A squelch system using EIA Standardized sub-
audible tones in the 67Hz to 250Hz frequency range. An FM squelch which opens only when the
proper sub-audible tone is present.
DIP Switch
Dual In-Line Package Switch (Also “dipswitch”)- A multi-unit switch that fits into a standard DIP
integrated circuit footprint. It usually contains eight or ten individual switches.
DTMF
Dual Tone Multi Frequency - The standard touch-tone telephone dialing method.
DSP
Digital Signal Processing (or Processor).
EIA
Electronic Industries Association.
Full Duplex
A communications system that can operate in transmit mode and receive mode simultaneously,
with different frequencies for transmit and receive. See also Half Duplex and Simplex.
Half Duplex
A communications system that uses different frequencies for transmit and receive operation, but
cannot transmit and receive at the same time. See also Full Duplex and Simplex.
Hangtime
A system with hangtime will remain in the transmit mode for the duration of the set hangtime
beyond the time indicated by any keying inputs. The hangtime prevents transmitter unkey during
brief pauses in the transmission.
Key
To key a transmitter means to cause it to transmit.
LED
Light Emitting Diode.
LMR
Land Mobile Radio.
Mute
To quiet or inhibit audio.
PCB
Printed Circuit Board.
PTT
Push-to-Talk. An active PTT signal causes a transmitter to key.
RX
Receiver or Receiving.
Simplex
A communications system that uses the same frequencies for both transmit and receive operation.
A simplex system can obviously not transmit and receive simultaneously. See also Full Duplex
and Half Duplex.
SNR
Signal-to-Noise Ratio.
Squelch
A means of detecting audio and causing some action when it is present, such as keying a
transmitter or unmuting an audio path.
TX
Transmit or Transmitter.
VOX
Voice Operated Xmit (Transmit). A circuit or algorithm that causes a transmitter to key or some
other action when voice or other signal is present. This squelch type is activated by any audio
signal, and is not restricted to voice only.

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RTU-292C Operations Manual
1-1
1General Information
1.1 SCOPE
This instruction manual provides the information necessary to install, operate, repair and
maintain the RTU-292C Radio/Telephone Interface.
1.2 DESCRIPTION
1.2.1 GENERAL
The RTU-292C Radio/Telephone Interface Unit will provide a trouble-free automatic connection
between a radio system and telephone or other two-wire line. The unit is suited for use with HF,
VHF, UHF or satellite systems and is applicable to full or half-duplex modes. The RTU-292C
incorporates a full-featured telephone set and monitor speaker. Flexible switching allows many
operating scenarios.
A front panel keypad allows DTMF or Pulse dialing and the built-in handset is pushbutton-
selectable for communication with either the telephone or the radio. Since the telephone may
place and receive calls, the operator can quickly and easily establish a phone patch connection.
When used in the manual mode, the RTU-292C patches a telephone into a radio link by
essentially the same method as with a conventional phone patch; the quality of the patch however
is greatly improved. First, a radio-to-radio link is established. Then, using the telephone in the
RTU-292C, the operator places a phone call to the distant telephone that will be patched into the
radio link. Once the telephone-to-telephone link is made, the operator simply pushes a front panel
pushbutton. The RTU-292C adapts to the phone line, and the distant phone becomes part of a
telephone-to-radio-to-radio communications link. Once this link is established, the operator may
communicate with either party using the RTU-292C’s handset, and may monitor both sides of
the conversation with the speaker.
The RTU-292C uses a unique adaptive hybrid implemented with a DSP (Digital Signal
Processor) to eliminate conventional VOX and hybrid adjustments for a quick and simple set-up.
The unit works by measuring the characteristics of the telephone line. A short burst of white
noise is placed on the telephone line. During this burst, the adaptive hybrid in the unit measures
the signal reflected from the phone line and adapts the RTU-292C to the impedance of the phone
line, minimizing the reflected signal. This achieves a broadband hybrid balance on the reactive
phone line. This is simply not possible with any type of conventional active or passive hybrid.
Not only is a deep, broadband null provided, but also the action is completely automatic. The
unit will continuously adapt to changing line conditions, making operation insensitive to line
impedance changes.
In the Automated Operations mode, the RTU-292C combines the unique features of its adaptive
DSP hybrid with fully unmanned auto-dial/auto-answer capability. In its standard configuration,
the unit uses tone prompts to signal the remote user of the operations that must be performed to
control the unmanned radio station. The addition of a Voice Prompt Option supplies a large
number of spoken prompts to simplify control. The Local Phone Option allows a standard

RTU-292C Operations Manual
1-2
telephone set to be plugged into the rear panel of the RTU-292C; this local phone may then be
used in place of the unit's keypad and handset.
Input and output levels are internally adjustable to accommodate all types of radio systems. A
set-up mode allows the adjustment of the RTU-292C receiver and transmitter signal levels
without any external test equipment.
The unit will interface all types of two-wire lines, such as normal dial-up lines, dedicated lines,
or twisted-pair field wire. Although the output impedance is fixed at 600 Ohms, the adaptive
hybrid in the unit will give excellent hybrid balance regardless of the impedance of the line
connected to the unit.
The unit operates from an external AC power supply (provided) that operates from 90 to 270
VAC, 47 to 63 Hz, or from +12 or +24/+28 VDC nominal; the +12VDC range extends from +11
to +15 VDC, while the +24/+28 VDC range extends from +22 to +30 VDC. It is packaged in a
rugged enclosure measuring 3.5"H x 19"W x 12"D. All inputs and outputs, including those for
power, are filtered or protected as appropriate to enable the RTU-292C to meet the requirements
of FCC Part 15 rules for a Class A Digital Device.
1.3 ASSEMBLIES
The standard RTU-292C contains five PC board assemblies; the main board (with plug-on
adaptive hybrid DSP board), three front panel switch PC board assemblies, and the Options
Interface Board, which is mounted in the Options Tray where other option boards may be
installed. Mounted on the front panel along with the switchboards are a speaker, control
potentiometers, and handset jack. The various I/O connectors and the DC power input
connectors are accessible via the rear panel.
1.3.1 MAIN BOARD
The main board has six general sections of circuitry: The Telephone Interface Section,
Handset/Speaker Interface Section, Radio Interface Section, DSP Section, CPU Section, and
Power Supply Section. These are described briefly in the following paragraphs.
1.3.1.1 Telephone Interface
The Telephone Interface Section has the amplifiers that drive and receive audio from the phone
line. This section also contains the DSP hybrid, interfaced with the keypad. A tone ringer
generates a warble audio tone when ring voltage is received.
1.3.1.2 Handset/Speaker Interface
The Handset/Speaker Interface Section contains the speaker pre-amp and driver, the handset pre-
amp and driver. Audio gates controlled by the front panel switches route the audio to the speaker
and handset microphone preamplifier and ALC (Automatic Level Control) circuit.
1.3.1.3 Radio Interface
The Radio Interface Section consists of operational amplifier circuits that handle the audio
interfaces between the RTU-292C and the radio. The amplifiers provide gain adjustability to
accommodate various input and output levels, and also provide impedance transformation and
output drive capability. Audio gates controlled by the front panel switches and the CPU route
the audio as desired by the operator.

RTU-292C Operations Manual
1-3
1.3.1.4 DSP Module
The plug-in Digital Signal Processor (DSP) module is the heart of the unit, as the adaptive hybrid
is implemented with the DSP. From a hardware standpoint, the DSP Section consists of a DSP
chip interfaced with dual analog interface ICs, static RAM for audio storage and delay, and a
program flash memory IC.
From a software standpoint, the following functions are implemented in software in the DSP
Section: the adaptive hybrid, the VOX, an audio peak detector, the noise generator for measuring
the telephone line characteristics, an audio delay and the transmit setup tone generator.
1.3.1.5 CPU Section
This section contains the microprocessor and program software that controls all operations of the
RTU-292C. Various I/O devices read external inputs and the front panel controls. The inputs
are processed and audio gates, front panel LEDs, audio prompts, etc., are controlled accordingly.
1.3.1.6 Power Supply Section
The power supply in the takes in DC current from either the supplied external AC supply or from
an external +12V (nom), +24V (nom), or +28V (nom) DC source. It furnishes regulated voltages
of +12V, -12V, +5V and -5V to the unit.
1.3.2 FRONT PANEL SWITCH ASSEMBLIES
There are three separate front panel switch assemblies that contain the pushbutton switches and
LED indicators for the RTU-292C. Each of these assemblies contains a different complement of
components as required by its function. Signals from the switches are read by the CPU circuitry
on the main board. The processor then routes audio signals and lights the front panel LEDs per
the pushbutton commands.
1.3.3 OPTIONS INTERFACE BOARD
This board, located on the Options Tray above the main board, contains the connectors used to
interface the main board to the various option boards that may be assembled to the Options Tray.

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1-4
Table 1-1 Equipment and Accessories Supplied
Qty
Part Number
Item
1
5020-500000
RTU-292C Standard
1
5020-500200
Operation & Maintenance Manual [this document]
1
5020 500150
Accessory Kit
Accessory Kit
Consists of:
Qty
Part Number
Item
1
0150-200000
Handset, PTT, Black, with coiled cord
2
0360-009000
Connector, cable, DB-9 receptacle
2
0650-005250
Fuse, 3AG, 5A, fast blow
2
0827-000001
HW, clamp, cable, for DB-9 connector
1
0827-102401
HW, Telephone Hangar
8
0833-063205
HW, screw, flat head, 6-32 x 5/16”, 100 degrees,
(spares for top cover mounting)
5
0837-103200
HW, Truss head screw for rack mounting (with one spare)
5
0848-100001
HW, Nylon washer for rack mounting (with one spare)
1
5020-502000
AC Power Supply, universal, 5A

RTU-292C Operations Manual
1-5
1.3.4 OPTIONS
RTU-292C options include the: The Voice Prompt Option, which gives verbal prompts to the
user as an aid in all aspects of unit operation as well as various Software Options. Several
different levels of spares kits are also available.
Table 1-2 Optional Equipment - Not Supplied
Item
P/N
Description
Depot Spares Kit
5050-591000
Spares for 3 to 5 RTU-292Cs
Spare PC Board Kit
5050-592000
Spare Boards and Installation Kit for 1 unit
Spare Parts Kit
5050-593000
Spares (except PCB) for one RTU-292C
Local Phone Option
5930-596000
[No longer available] Allows remote operation of the RTU-
292C through the use of a standard telephone set connected
directly to the RTU-292C Local Phone port
Voice Prompt Option
5930-595000
Standard Version (English, female voice; other languages
available)
Rack Slides Kit
5930-594000
1 set slides and hardware to rack-mount one RTU-292C.
Software Options
Call Logging S/W Option
5970-791500
Provides record of calls via RS-232 interface.
Radio Control Option
5970-795000
Provides remote control of URC-200 radio via RS-232 int.
Squelch Break Access
5970-791300
Allows radio connection via series of squelch breaks
DTMF Access Option
5970-799000
Allows radio connection via DTMF keypad.

RTU-292C Operations Manual
1-6
Table 1-3 RTU-292C Specifications
TELEPHONE LINE INTERFACE (J1, RJ-11 Connector)
Output & Input Levels to Phone Line
Nominally -12 dBm. (Adjustable -21 to 0 dBm in 3 dB steps).
Frequency Response
+2 dB, 300 to 3200 Hz.
Output Impedance to Phone Line
600 Ohms.
VOX Sensitivity
16 +2 dB Below Phone Line Input Level Setting. (-
25 dBm @ -9 dBm Level Setting, for example)
VOX Hang Time
0.6 Second or 2.0 Seconds, (Internally Settable).
Hybrid Balance/Adaptation Speed
(into 600 Ohm)
-30 dB over 300 to 3200 Hz BW within 1.25 Sec.; measured with
white noise source.
Ultimate Hybrid Balance (into 600 Ohm)
-50 dB typical over 300 to 3200 Hz BW; measured with single tone.
Hybrid Impedance Matching Capability
0 to 10k Ohm Complex Impedance.
RADIO INTERFACE (P1, Male DB-9 Connector)
Input Impedance
Balanced or Unbalanced 600 Ohm or Unbalanced 47K Ohm.
Input Level
-40 to +10 dBm, Internally Adjustable.
Output Impedance
600 Ohm balanced.
Output Level
-40 to +10 dBm, Internally Adjustable
Frequency Response
300 to 3200 Hz + 2 dB.
Key Relay Output
Low Level Relay Contacts, 60VA max., Switching Speed: 5 msec.
GENERAL
Handset (RJ12C Jack)
Electret microphone, dynamic receiver.
Dialing Modes
DTMF, Pulse at 10 pps
Pulse Dial Make/Break Ratio
40/60.
Dialing Keypad
3x4, Standard Telephone Layout.
Microphone Interface
ALC (Automatic Level Control) with 30 dB dynamic range.
Speaker Driver Power
4W min @ 10% Distortion.
Internal Speaker
3-inch square, 3.2 Ohms.
Indicators
Peak Level, Keyed, and Indicator for each pushbutton.
Front Panel Controls
Power Switch, Dialing Keypad, Speaker and Handset Volume
Controls, Pushbuttons: Tel Line/Phone, Tel Line/Radio, Off,
Handset/Phone, Handset/Radio, Speaker/Phone, Speaker/Radio, Tel
VOX, Manual Key, Auto Answer, Audible Ring.
AC Input Power (External Supply)
90 to 270 VAC, 47-63 Hz, 20 VA typical, 50 VA max.
DC Input Power
+11 to +15VDC or +22 to +30VDC, 1 A Maximum.
Size
3.5"H x 19"W x 10"D (8.9 x 48.3 x 25.4 cm)
Weight
9 lbs. (4 kg).
ENVIRONMENTAL
Operating Temperature
-200 C to +550 C.
Storage Temperature
-400 C to +850 C.
Humidity
Up to 95% @ 550 C.
Shock
MIL-STD-810D, method 516.3 procedure VI.
Vibration
MIL STD 810D, method 514.3 Category I.
REGULATORY COMPLIANCE
FCC part 15
Emissions for US and Canada
FCC Part 68
Phone line test
End of Section 1

RTU-292C Operations Manual
2-1
2Installation
2.1 GENERAL
This section provides the instructions for unpacking, inspection, installation and set-up. Also
included are directions for reshipment of damaged parts or equipment.
2.2 UNPACKING AND INSPECTION
After unpacking the unit, retain the carton and packing materials until the contents have been
inspected and checked against the packing list. If there is a shortage or any evidence of damage,
do not attempt to use the equipment. Contact the carrier and file a shipment damage claim. A
full report of the damage should also be reported to the Customer Service Department. The
following information should be included in the report:
1. Order Number
2. Equipment Model and Serial Numbers
3. Shipping Agency
4. Date(s) of Shipment
The Customer Service Department can be reached by phone at [phone] by fax at (919)
790-1456. Upon receipt of this information, we will arrange for repair or replacement.
2.3 RESHIPMENT OF EQUIPMENT
If it is necessary to return the equipment to the manufacturer, a Returned Material Authorization
(RMA) number must first be obtained from us. This number must be noted on the outside of the
packing carton and on all accompanying documents. When packing the unit for reshipment, it is
best to use the original packaging for the unit; if this is not possible, special attention should be
given to providing adequate packing material around connectors and other protrusions, such as
front panel controls. Rigid cardboard should be placed at the corners of the unit to protect against
corner damage during shipment. Failure to protect the corners of the front panel causes the most
common type of shipping damage experienced on returned equipment.
Shipment should be made prepaid consigned to:
JPS Interoperability Solutions
RMA Number XXXX
5800 Departure Drive
Raleigh, North Carolina 27616
USA

RTU-292C Operations Manual
2-2
Plainly mark with indelible ink all mailing documents as follows:
U.S. GOODS RETURNED FOR REPAIR
Mark all sides of the package:
FRAGILE - ELECTRONIC EQUIPMENT
Inspect the package prior to shipment to be sure it is properly marked and securely wrapped.
2.4 INSTALLATION OVERVIEW
SAFETY NOTE
The installation steps in the remainder of this section are intended to be performed
by a trained technician only and should not be performed by the communications
system operator.
SAFETY NOTE
Safety Disconnect Devices Information:
•If the RTU-292C is connected to a battery backup, there should be an
approved disconnect device installed in the DC wiring in an easily accessible
location.
•If the RTU-292C is being operated from a power source other than the
external supply provided, there should be an approved disconnect device
installed in the DC wiring in an easily accessible location.
Follow these four steps to properly install the RTU-292C:
1. Provide mechanical mounting for the unit. (Rack slides or shelves are required for 19" rack
mounting)
2. Provide the proper primary power for the unit.
3. Interconnect the unit with the radio and system as appropriate.
4. Check Section 0 to ensure that the unit is adjusted and configured as desired.
The RTU-292C is then ready to begin normal operation.