PairGain HLU-319 User manual

HIGAIN LINE UNIT
PAIRGAIN TECHNOLOGIES, INC.
ENGINEERING SERVICES TECHNICAL PRACTICE
SECTION 150-319-154-04
Model List Number Part Number CLEI Code
HLU-319 5D 150-1140-54 T1L2B30A
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HLU-319
HG HDIAIN
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150-319-154-04, Revision 04
ii September 29, 1999 HLU-319 List 5D
Revision History of This Practice
© Copyright 1999 PairGain Technologies, Inc.
PairGain andHiGain areregistered trademarks of PairGain Technologies, Inc. All other product namesmentionedin this practice
are used for identification purposes only and may be trademarks or registered trademarks of their respective companies.
Information contained in this document is company private toPairGain Technologies, Inc., and shall not be modified, used, copied,
reproduced or disclosed in whole or in part without the written consent of PairGain.
Information furnished by PairGain Technologies is believed to be accurate and reliable. However, no responsibility is assumed by
PairGain Technologies for its use; nor for any infringement of patents or other rights of third parties which may result from its use.
No license is granted by implication or otherwise under any patent or patent rights of PairGain Technologies. PairGain
Technologies reserves the right to change specifications at any time without notice.
Revision Release Date Revisions Made
01 December 18, 1998 Initial release
02 April 6, 1999 •Remove FRMG option.
•Add 31-day Performance History Screen
•Revise Power Consumption Tables.
03 July 9, 1999 •Firmware enhancements
•Addition of troubleshooting screens
04 September 29, 1999 •Firmware enhancements
•Enhanced troubleshooting screens

150-319-154-04, Revision 04 Using This Technical Practice
HLU-319 List 5D September 29, 1999 iii
USING THIS TECHNICAL PRACTICE
The following conventions are used in this manual:
•Monospace type indicates screen text, including text you type at a screen prompt.
•Keys you press are indicated by small icons such as . Key combinations to be pressed simultaneously
are indicated with a plus sign as follows: + .
•Three types of messages, identified by icons, appear in text.
For a list of abbreviations used in this document, refer to “Appendix E - Glossary” on page 60.
DOCUMENTATION
If you have comments on this PairGain document, send an email to technical_publicatio[email protected]m. Type
the product name and the section number of the document in the subject area of the email message.
INSPECTING THE SHIPMENT
Upon receipt of the equipment:
•Unpack each container and visually inspect the contents for signs of damage. If the equipment has been
damaged in transit, immediately report the extent of damage to the transportation company and to PairGain.
Order replacement equipment, if necessary.
•Check the packing list to ensure complete and accurate shipment of each listed item. If the shipment is short
or irregular, contact PairGain as described in the Warranty located inside the back cover. If you must store
the equipment for a prolonged period, store the equipment in its original container.
Notes contain information about special circumstances.
Cautions indicate the possibility of equipment damage or personal injury.
The Electrostatic Discharge (ESD) Susceptibility symbol indicates that a device or assembly is
susceptible to damage from electrostatic discharge.
ENTER
CTRL ESC

Inspecting the Shipment 150-319-154-04, Revision 04
iv September 29, 1999 HLU-319 List 5D

150-319-154-04, Revision 04 Table of Contents
HLU-319 List 5D September 29, 1999 v
TABLE OF CONTENTS
Overview ____________________________________________________________________________ 1
Features..............................................................................................................................................1
Product Enhancements ........................................................................................................1
Standard Features ................................................................................................................2
Compatibility .....................................................................................................................................2
Applications .......................................................................................................................................2
HiGain Doubler Applications..............................................................................................3
Personal Communications System Applications.................................................................3
Front Panel __________________________________________________________________________ 4
Installation___________________________________________________________________________ 8
Verification ........................................................................................................................................9
Verification without a Downstream Device........................................................................9
Verification with a Downstream Device .............................................................................9
Provisioning Requirements..............................................................................................................10
Provisioning_________________________________________________________________________ 10
Using the MODE and SEL Buttons.................................................................................................10
Setting Options through MODE and SEL.........................................................................10
Resetting to Factory Default Values..................................................................................11
Displaying System Parameter Settings..............................................................................11
Disabling an Alarm............................................................................................................11
Loopback Modes ...............................................................................................................11
Using a Maintenance Terminal........................................................................................................12
Connecting to a Maintenance Terminal.............................................................................12
Accessing the Maintenance Terminal Screens..................................................................12
Navigation Keys..................................................................................................12
Maintenance Terminal Main Menu.....................................................................13
Selecting a Maintenance Terminal Function.......................................................14
System Spans.......................................................................................................14
Using the Maintenance Terminal Screens .......................................................................................14
View Span Status Screen...................................................................................................14
Span Status Screen without Doublers .................................................................15
Span Status Screen for Doubler Applications.....................................................15
Set Clock Screen................................................................................................................18
Set Time ..............................................................................................................18
Set Date...............................................................................................................18
Update the HRU Time and Date .........................................................................18

Table of Contents 150-319-154-04, Revision 04
vi September 29, 1999 HLU-319 List 5D
System Settings Screen..................................................................................................... 19
BPVT Option...................................................................................................... 21
BER Option ........................................................................................................ 22
Margin Alarm Threshold Option........................................................................ 22
HDSL Line Voltage Options.............................................................................. 22
Loopback Mode Screen .................................................................................................... 23
Loopback Menu without Doubler....................................................................... 24
Loopback Menu for Doubler Applications......................................................... 24
Initiating a Loopback.......................................................................................... 25
Disabling a Loopback......................................................................................... 25
View Performance Data Screen........................................................................................ 26
Performance Data Screen without Doubler........................................................ 27
Performance Data Screen for Doubler Applications.......................................... 27
View Performance History Screen (7-Day and 31-Day) .................................................. 28
Performance History Screen without Doubler.................................................... 28
Performance History Screen for Doubler Applications (7-Day and 31-Day) .... 29
View Alarm History Screen.............................................................................................. 30
Alarm History Screen without Doubler.............................................................. 31
Alarm History Screen for Doubler Applications................................................ 31
System Inventory Screen .................................................................................................. 32
System Inventory Screen without Doubler......................................................... 33
System Inventory Screen for Doubler Applications........................................... 33
View Troubleshooting Screen........................................................................................... 34
Troubleshooting _____________________________________________________________________ 38
System Alarms................................................................................................................................. 38
Alarm Option for Digital Loop Carrier (DLC) Feed ........................................................ 39
Retiring System Alarms.................................................................................................... 39
Self Test ............................................................................................................................ 39
Loopback Operation........................................................................................................................ 39
A5LB Loopback Commands ............................................................................................ 40
Manual Loopback Session ................................................................................................ 41
Setting the Loopback Time-out Option.............................................................. 41
Initiating a Manual Loopback Session ............................................................... 42
Loopback Test Procedure................................................................................................................ 43
General Troubleshooting Tips .......................................................................................... 43
A5LB Test Procedure........................................................................................................ 44

150-319-154-04, Revision 04 Table of Contents
HLU-319 List 5D September 29, 1999 vii
Appendix A - Specifications____________________________________________________________ 46
HDSL Insertion Loss Guidelines.....................................................................................................47
Power Consumption.........................................................................................................................47
Power Consumption without Doublers..............................................................................47
Power Consumption with Doublers...................................................................................48
Maximum Power Dissipation...........................................................................................................50
Maximum Current Drain..................................................................................................................50
HLU-319 Card-edge Connector.......................................................................................................51
Network Management Control Bus...................................................................................51
Fuse Alarm ........................................................................................................................51
System Alarm Output........................................................................................................52
Craft Port..........................................................................................................................................53
Appendix B - Functional Operation _____________________________________________________ 54
Timing..............................................................................................................................................55
Ground Fault Detect.........................................................................................................................55
Appendix C - Compatibility ___________________________________________________________ 56
T1 Repeater Shelves and Related Equipment..................................................................................56
HiGain Doubler Circuit Deployment...............................................................................................56
Appendix D - Product Support _________________________________________________________ 58
Technical Support............................................................................................................................58
World Wide Web .............................................................................................................................58
Returns.............................................................................................................................................58
Appendix E - Glossary________________________________________________________________ 60
Certification and Warranty______________________________________________ Inside Back Cover

List of Figures 150-319-154-04, Revision 04
viii September 29, 1999 HLU-319 List 5D
LIST OF FIGURES
1. HLU-319 List 5D Front Panel........................................................................................................................ 4
2. Installing the HLU-319 into a Shelf ............................................................................................................... 8
3. Maintenance Terminal Main Menu .............................................................................................................. 13
4. System Spans................................................................................................................................................ 14
5. Span Status Screen: No Doubler................................................................................................................... 15
6. Span Status Screen: Four Doublers (Span 5)................................................................................................ 15
7. Set Clock Screen........................................................................................................................................... 18
8. System Settings Screen................................................................................................................................. 19
9. Loopback Menu: No Doubler....................................................................................................................... 24
10. Loopback Menu: Four Doublers................................................................................................................... 24
11. NLOC Loopback Mode Reported in the Maintenance Terminal Main Menu.............................................. 25
12. Performance Data Screen: No Doubler......................................................................................................... 27
13. Performance Data Screen: Four Doublers (Span 5)...................................................................................... 27
14. 7-Day Performance History Screen: No Doubler......................................................................................... 28
15. 31-Day Performance History Screen: Four Doublers (Span 5).................................................................... 29
16. Alarm History Screen: No Doubler.............................................................................................................. 31
17. Alarm History Screen: Four Doublers (Span 5) ........................................................................................... 31
18. System Inventory Screen: No Doubler......................................................................................................... 33
19. System Inventory Screen: Four Doublers..................................................................................................... 33
20. Troubleshooting Screen for an Operational System..................................................................................... 34
21. Troubleshooting Screen Identifying Circuit Problems................................................................................. 34
22. Troubleshooting with Help........................................................................................................................... 35
23. Troubleshooting with Margin Values........................................................................................................... 36
24. Troubleshooting with Insertion Loss Values................................................................................................ 36
25. Troubleshooting with Errored Seconds Values ............................................................................................ 37
26. Troubleshooting with Unavailable Seconds Values..................................................................................... 37
27. Loopback Summary...................................................................................................................................... 39
28. Supported Loopback Configurations............................................................................................................ 43
29. HLU-319 List 5D Card-edge Connector ...................................................................................................... 51
30. RS-232 Craft Port Pinouts ............................................................................................................................ 53
31. HLU-319 Block Diagram ............................................................................................................................. 54

150-319-154-04, Revision 04 List of Tables
HLU-319 List 5D September 29, 1999 ix
LIST OF TABLES
1.Front Panel Description....................................................................................................................................5
2.Front Panel Display Messages..........................................................................................................................6
3.Navigational Keys on the Maintenance Terminal..........................................................................................12
4.Maintenance Terminal Screens ......................................................................................................................13
5.Span Status Fields and Descriptions...............................................................................................................16
6.HDSL System Alarms....................................................................................................................................17
7.Loopback Messages........................................................................................................................................17
8.HLU-319 System Settings..............................................................................................................................20
9.Loopback Field Messages and Descriptions ..................................................................................................23
10.Errored and Unavailable Seconds Definitions ...............................................................................................26
11.Alarm History Fields and Descriptions..........................................................................................................30
12.HDSL System Alarms....................................................................................................................................38
13.Summary of HiGain Loopback Codes ...........................................................................................................40
14.Addressable Repeater Loopback Commands.................................................................................................44
15.HDSL Loss Over Cables................................................................................................................................47
16.Power Parameters—No Doubler....................................................................................................................47
17.Power Parameters—Single Doubler (HDU-451 List 1 or 2)..........................................................................48
18.Power Parameters—Single Doubler (HDU-439 or HDU-437 Lists 1 and 1B)..............................................48
19.Power Parameters—Single Doubler (HDU-404 List 2, HDU-407 List 2, and HDU-409 List 2)..................48
20.Power Parameters—Two Doublers (HDU-451 List 3, 4, 3B or 4B)..............................................................49
21.Power Parameters—Two Doublers (HDU-439 or HDU-437 Lists 1 and 1B)...............................................49
22.Power Parameters—Two Doublers (HDU-404 List 2, HDU-407 List 2, and HDU-409 List 2)...................49
23.Power Parameters—Three or Four Doublers (HDU-404 List 2, HDU-407 List 2, and HDU-409 List 2)....49
24.HiGain Doubler Deployment Matrix..............................................................................................................57

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150-319-154-04, Revision 04 Overview
HLU-319 List 5D September 29, 1999 1
OVERVIEW
The PairGain®HiGain®Line Unit HLU-319 List 5D is the Central Office (CO) side of a repeaterless
T1 transmission system. When used in conjunction with a HiGain Remote Unit (HRU), the system provides
1.544 Mbps transmission on two unconditioned copper pairs over the full Carrier Service Area (CSA) range. The
CSA includes loops up to 12,000 feet of 24 American Wire Gauge (AWG) or 9,000 feet of 26 AWG wire,
including bridged taps. This line unit can be used with HiGain Doubler Units (HDUs) to extend reach.
FEATURES
Product Enhancements
•Fast Loss of Sync Word (LOSW) reporting
•Five-span range with four doublers (60 kft, 24 AWG)
•Four line-powered spans (three doublers and one remote)
•Reduced power consumption
•Ultra-low wander (Stratum 1 compliant)
•Low line-power option (-135 V) for circuits with a single doubler
•Selectable Power Feed (PWRF) modes: Auto, High, Low, and Disabled
•Grounded loop detection on High-bit-rate Digital Subscriber Line (HDSL)
•Bipolar Violation Transparency (BPVT) options
•Bit Error Rate (BER) alarm options
•HRU loopback screen
•Inventory Screen (displays Circuit ID and unit IDs)
•Loss of Signal/Alarm Indicator Signal (LOS/AIS) payload alarm option
•Remote Loss of Signal (RLOS) disable alarm option
•Supports HRU-411 in Personal Communication Services (PCS) applications
•Default setting screen option
•Payload (PL) or HiGain (HG) loopback source identification
•Remote provisioning
•Troubleshooting screen

Overview 150-319-154-04, Revision 04
2 September 29, 1999 HLU-319 List 5D
Standard Features
•Selectable DS1 pre-equalizer
•Front panel features:
–Four-character status display
–DSX-1 splitting and bridge access
–Status Light Emitting Diode (LED)
–RS-232 craft port for connection to a maintenance terminal
•Compatible with SXSS shelves, and equivalent
•Selectable loopback activation codes
•Network Management and Administration (NMA) interface
•Lightning and power cross protection on HDSL interfaces
•Full duplex 2B1Q HDSL transmission on two pairs at 784 kbps
•Margin threshold alarm
The HLU-319 List 5D has fewer user front panel options than the HLU-319 List 5. See “HLU-319 System
Settings”on page 20 for additional information.
COMPATIBILITY
The HLU-319 is designed to mount into 3192 mechanics shelves. For a list of compatible shelves, see “Appendix
C - Compatibility”on page 56.
All generations of HiGain HLU and HRU modules are compatible with each other. To take advantage of the
enhanced features of newer HiGain doublers, refer to “HiGain Doubler Circuit Deployment”on page 56.
APPLICATIONS
HiGain systems provide a cost-effective, easy-to-deploy method for delivering T1 High Capacity Digital Service
(HCDS) over metallic pairs.
•The service is deployed over two unconditioned, non-loaded copper pairs, yet it demonstrates a quality that
is competitive with fiber optics.
•Conventional, in-line, T1 repeaters are not required.
•Cable pair conditioning, pair separation and bridged tap removal are not required.
In general, HiGain systems do as follows:
•Operate with any number of other T1, Plain Old Telephone Service (POTS), Digital Data Service (DDS) or
other HiGain systems sharing the same cable binder group.
•Can be used with customers requiring DS1 service on a temporary or permanent basis.
•Provide a means of quickly deploying service in advance of fiber-optic transmission systems.
With a HiGain system, service can be provided within hours. Fiber-optic systems can be installed incrementally
and cut over from the installed HiGain system when convenient to do so.

150-319-154-04, Revision 04 Overview
HLU-319 List 5D September 29, 1999 3
HiGain Doubler Applications
For applications without doublers, the HLU-319 is directly connected to the HRU by the two HDSL cable pairs.
The HLU-319 is compatible with all HiGain HRUs.
For doubler applications, one to four doublers may be used in the HDSL loops between the HLU and HRU.
•The HLU-319 can power three doublers and a remote unit (HRU-402 or HRU-411) for a total of four spans.
•If the HRU is locally powered, the HLU can power up to four doublers for a total of five spans.
Personal Communications System Applications
The HLU-319 is required for Personal Communications System (PCS) applications that use the HRU-411. The
HRU-411 has an onboard 130 V, 8.5 W power supply that can power the 200 mW PCS remote radio ports. The
HLU recognizes the HRU-411, if the Customer Premises Equipment (CPE) power switch is set to ON, and
performs the following two functions required by the HRU-411 to bring up the National Electric Code (NEC)
radio port:
•Increases the HDSL line voltage to its high ±112 V level with the PWRF option set to AUTO
•Enables HRU-411 to turn on its floating 130 V radio port supply
These extended ranges are only available when using the HDU-409, HDU-404 or HDU-407
micro-doublers with the HRU-411 or HRU-402. Older doublers (HDU-451, HDU-439 and HDU-437)
cannot be used in circuits with more than two doublers in any line or local power system. For
compatibility guidelines on mixing newer doublers with older HRU and HLU models, refer to
“HiGain Doubler Circuit Deployment”on page 56.
For additional information about associated HiGain equipment, refer to the respective HiGain
technical practice (see “Appendix D - Product Support”on page 58).

Front Panel 150-319-154-04, Revision 04
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FRONT PANEL
The HLU-319 List 5D front panel is shown in Figure 1. The front panel components are described in Table 1 on
page 5. For pinout diagrams of the card-edge connector and the craft port, refer to “HLU-319 Card-edge
Connector”on page 51.
Figure 1. HLU-319 List 5D Front Panel
S
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HLU-319
HiGain HD
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System option buttons
Front-panel display
Craft port
DSX-1 access jacks
CLEI/ECI bar code label
(on outside of handle)
Status LED
SETUP
STATUS
List number
Configuration number label
(on inside of handle)
Card handle

150-319-154-04, Revision 04 Front Panel
HLU-319 List 5D September 29, 1999 5
Table 1. Front Panel Description
Front Panel Feature Function
Front panel display Displays four-character status, provisioning, and alarm system messages.The front panel display
illuminates when power is initially applied. To conserve power the display only remains on for
4 minutes. Using the MODE or SEL buttons reactivates the display and restarts the 4-minute timer.
Refer to Table 2 on page 6 for a listing of the four-character messages.
System option buttons
(MODE and SEL)
Permits the user options to be monitored and modified without the need of a maintenance terminal.
Used to initiate all HiGain loopbacks and to display DSX-1 line parameters and line unit identity.
Status LED The status LED can report the following conditions:
Green Normal operation.
Flashing green HDSL acquisition.
Red Fuse Alarm.
Flashing red System alarm.
Yellow Self Test is in process or an HLU-319 Customer Remote Loopback (CREM) or a Network Local
Loopback (NLOC) is in effect.
Flashing yellow HLU-319 is in an Armed state.
DSX-1 access jacks
BRG Provides non-intrusive bridging jack access to (XMT) and from (RCV) the HDSL span at the DSX-1
interface. Allows the two T1 payloads to be monitored.
LINE Provides splitting jack access to (XMT) and from (RCV) the HDSL span at the DSX-1 interface.
Breaks the XMT and RCV paths to permit test signal insertion and retrieval.
RS-232 craft port Provides bidirectional communication between the unit and an external terminal to allow
configuration and performance monitoring through the Maintenance Terminal screens.
CLEI and ECI bar code label Provides the human-readable Common Language Equipment Identifier (CLEI) code number and the
Equipment Catalog Item (ECI) bar code number.
List number Identifies the version of the HLU-319.
Configuration number Contains either a five or six-digit warranty configuration number or a stand-alone two or three-digit
configuration number as follows:
Digit 1 - Last digit of shipment year
Digit 2 and 3 - Shipment month
Digits 4, 5, and 6 - Configuration number
The configuration number can also be found on a small bar label that contains the Julian date code
and part number. This gummed label may be affixed to the PC board or to the front panel.

Front Panel 150-319-154-04, Revision 04
6 September 29, 1999 HLU-319 List 5D
Table 2. Front Panel Display Messages
Message Full Name Description
ALARM MESSAGES
ACO Alarm CutOff A system alarm has occurred and has been retired to an ACO
condition by pressing the SEL button on the HLU front panel.
ALRM Alarm Condition Exists A system alarm condition is in effect.
BER Bit Error Rate A system BER alarm is in effect.
LLOS Local Loss of Signal Indicates that no signal is detected at the DSX-1 input to the HLU.
LOSW Loss of Sync Word Indicates that one of the HDSL loops has lost its synchronization.
The Fast LOSW feature is enabled when the Bipolar Violation
Transparency (BPVT) option is enabled (see “BPVT Option” on
page 21).
MAL1 or MAL2 Margin Alarm Loop 1 or Loop 2 The margin on HDSL Loop 1 or Loop 2 has dropped below the
threshold (1 to 15 dB) as set by the operator.
RLOS Remote Loss of Signal Indicates that no signal is detected at the DS-1 input to the HRU.
LOOPBACK MESSAGES
ARM HiGain System Armed Armed to respond to Intelligent Repeater Loop Codes.
CDUnCustomer Doubler nLoopback Query to initiate loopback at doubler n to CI, where nis the number
of the doubler.
CLOC Customer Local Loopback Signal from customer is looped back to the customer at the HRU.
CREM Customer Remote Loopback Signal from customer is looped back to the customer at HLU-319.
NDUnNetwork Doubler nLoopback Query to initiate loopback at doubler n to network, where nis the
number of the doubler.
NLOC Network Local Loopback DSX-1 signal is looped back to DSX-1 at HLU.
NREM Network Remote Loopback DSX-1 signal is looped back to DSX-1 at the HRU.
SMJK Remote SmartJack Loopback Signal from DSX-1 is looped back at the HRU by the HRU SmartJack
module.
TLOS Transmit Loss of Signal DSX-1 signal is looped back to the DSX-1 interface at the HRU. The
HRU is in a logic loopback state caused by a loss of its DS-1 input
from the CI, if enabled at the HRU by its TLOS switch option.

150-319-154-04, Revision 04 Front Panel
HLU-319 List 5D September 29, 1999 7
DIAGNOSTIC MESSAGES
1=xx or 2=yy HDSL Loop Margins Indicates the power of the received HDSL signal on each loop
relative to noise. Any value of 06 or greater is adequate for reliable
system operation.
ACQ1 or ACQ2 Acquisition 1 or Acquisition 2 The multiplexers of the HLU and HRU or first doubler are trying to
establish synchronization over Loop 1 or Loop 2 of Span 1.
AnL1 or AnL2 Acquisition nLoop 1or Loop 2 The multiplexers of the two devices on Span nare trying to establish
synchronization with each other on Loop 1 or Loop 2, where nis the
number of the span.
BAD RT? No response from HRU The HLU does not receive any response from the HRU. Thus, the
integrity of the HRU or the two HDSL loops (which may be open) is
questionable.
CODE xxxx Line Code: AMI, B8ZS The Line Code is set to either of the two DS1 line code settings,
Alternate Mark Inversion (AMI) or Bipolar with 8-zero Substitution
(B8ZS). Displayed during System Settings review mode.
FRM Frame: SF, ESF, THRU, NONE Defines the type of frame pattern being received from the DSX-1:
SuperFrame (SF), Extended SuperFrame (ESF), or THRU. If no
frame pattern is being received, NONE displays. Displayed during
System Settings review mode.
H1ES or H2ES HDSL CRC Error Loop 1 or Loop 2 HDSL Loop 1 or Loop 2 CRC error.
nHDU Number of Doublers This message indicates the number (n) of doublers in the circuit.
INSL, then xxDB Maximum Insertion Loss The Maximum Insertion Loss message (INSL) appears followed by
xxDB, where xx is the maximum insertion loss in dB of all spans and
loops.
LBPV Local Bipolar Violation A bipolar violation has been received at the DSX-1 input to the
HLU-319.
LIST xxxx HLU-319 list number The software list number appears during the System Settings review
mode. Press the MODE button for 3 seconds to display the list
number.
MNGD Managed The HLU is under control of the HMU-319 Network Management
Unit. In this state, the front panel craft port and pushbuttons are
disabled.
PWR FEED GND Power Feed Ground One of the HDSL loops has been grounded.
PWR FEED ON Power Feed On Indicates that the HDSL loops are not grounded or shorted.
PWR FEED OFF Power Feed Off HDSL span power has been turned off by setting the PWFD option
to DIS, or HDSL span power has been turned off by use of the A5LB
Intelligent Office Repeater (IOR) Power Down code.
PWR FEED SHRT Power Feed Short Indicates a short between the two HDSL pairs. This same message
can occur with an HRU that is drawing the correct amount of power
over good cable pairs but cannot communicate with the HLU.
SELF TEST Self Test The HLU is in a self-test mode. This occurs every power On/Off
cycle.
SIG1 or SIG2 Signal 1 or Signal 2 The transceivers of the HLU and HRU or first doubler are trying to
establish contact with each other on Loop 1 or Loop 2 of Span 1.
SnL1 or SnL2 Signal nLoop 1 or Loop 2 The transceivers of the two devices on Span nare trying to establish
contact with each other on Loop 1 or Loop 2, where nis the number
of the span.
VER xxxx HLU-319 software version number The software version number appears during the System Settings
review mode. Press the MODE button for 3 seconds to display the
software version.
Table 2. Front Panel Display Messages (Cont.)
Message Full Name Description

Installation 150-319-154-04, Revision 04
8 September 29, 1999 HLU-319 List 5D
INSTALLATION
Slide the HLU-319 into the card guides for the desired slot, then push the unit back until it seats firmly in the
backplane card-edge connector (Figure 2).
Figure 2. Installing the HLU-319 into a Shelf
Upon receipt of the equipment, visually inspect the contents for signs of damage. If the
equipment has been damaged in transit, immediately report the extent of damage to the
transportation company and to PairGain Technologies.
When installing an HLU in a chassis, be sure to wear an antistatic wrist strap. Avoid touching
components on the circuit board.

150-319-154-04, Revision 04 Installation
HLU-319 List 5D September 29, 1999 9
VERIFICATION
Once the HLU-319 is installed, verify that it is operating properly. To do this, monitor the following:
•Status LED
•Status messages reported by the front panel display (Table 2 on page 6)
Verification without a Downstream Device
If there is no downstream device installed:
1Verify that the HLU powers up. (The front panel display illuminates and reports four-character status
messages. See Table 2 on page 6 for a list of messages.)
2Verify that the HLU attempts to communicate with downstream devices. Even if a downstream device is not
present, the following events should occur:
aThe front panel display reports four-character status messages.
bThe HLU enters self-test mode (Status LED is yellow).
cThe HLU again attempts communication with downstream devices, repeating events athrough buntil a
downstream device is successfully detected.
Verification with a Downstream Device
If a downstream device has been installed:
1Verify that the HLU powers up. (The front panel display illuminates and reports status messages.)
2Verify that the HLU attempts to communicate with downstream devices (status LED flashes green). One of
the following occurs:
•If downstream devices are successfully identified and the HDSL loops synchronize, the HLU status LED
will be a steady green. The HLU reports normal margin messages on the front panel display.
•If downstream devices are not successfully identified, the HLU reports four-character status messages
and enters self-test mode. The HLU successively
–enters self-test mode
–completes self-test mode
–attempts communication again
–reports four-character status messages.
The HLU repeats this cycle until a downstream device is detected.
3If there is more than one span, verify that each subsequent span synchronizes normally by monitoring the
front panel display messages.
4If a remote unit is installed, verify that the last span synchronizes normally. The HLU status LED should be
a steady green, and the front panel display reports normal margin messages.
5Verify that a valid T1 signal has been applied to the HLU and the HRU.
•If no T1 signal is being applied to either the HLU or the HRU inputs, then the appropriate T1 alarms
(LLOS or RLOS) are observed on the front panel display and the status LED flashes red.
•If a valid T1 signal is being supplied to the HLU and HRU, then T1 alarm indications should be absent
and the status LED should be a steady green.

Provisioning 150-319-154-04, Revision 04
10 September 29, 1999 HLU-319 List 5D
PROVISIONING REQUIREMENTS
Refer to “Provisioning”on page 10 for information about using the MODE and SEL buttons or the Maintenance
Terminal screens to configure the HLU. While the MODE and SEL buttons can be used to manually accomplish
some provisioning tasks, such as setting system options, the Maintenance Terminal screens (available when you
connect a PC to the craft port) can handle all provisioning tasks. Tasks that you need to complete are:
1Set the time and date (see “Set Clock Screen”on page 18).
2Set the circuit IDs (see “System Inventory Screen”on page 32).
Once the HLU has been successfully installed and provisioned, complete the following to ensure an accurate
Alarm History and Performance History.
1Clear Span Status screens (see “View Span Status Screen”on page 14). Clearing the Span Status screens also
clears the Performance Data and Performance History screens.
2Clear the Alarm History screens (see “View Alarm History Screen”on page 30).
PROVISIONING
There are two methods for provisioning the HLU-319 List 5D:
•Use the MODE and SEL buttons on the HLU front panel to
–set system options.
–reset the HLU to the factory default settings for system options.
–display system option settings (scroll mode).
–select system loopbacks.
•Use a maintenance terminal (ASCII terminal or a PC running terminal emulation software) connected to the
HLU craft port to access the Maintenance Terminal Main Menu (Figure 3 on page 13). This gives you full
access to all HLU status, history, inventory, and provisioning screens.
USING THE MODE AND SEL BUTTONS
Setting Options through MODE and SEL
To provision the HLU-319 through the MODE and SEL buttons on the front panel:
1Press the MODE button for 2 seconds and then release it. The front panel display alternately shows the first
system parameter and its current setting.
2Press the SEL button to step the display through all possible settings (one at a time) of the selected parameter.
3After the desired setting has been selected, press the MODE button. This updates the current displayed
parameter to the selected setting, and then advances to the next configurable parameter. After the last
parameter has been selected, a CONF NO message appears on the front panel display.
No dip switches or jumpers are required to provision the HLU-319 as it contains a Non-volatile
Random Access Memory (NVRAM) which stores the system option settings. System option
settings are retained if shelf power is lost or if the HLU-319 is unplugged.