PairGain HLU-231 User manual

2 HLU-231 List 8E Technical Practice
THE HLU-231 LIST 8E
The PairGain®HiGain®Line Unit HLU-231 List 8E 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
AWG or 9,000 feet of 26 AWG wire, includingbridged taps. This lineunit can be used in applications with or without HiGain
Doubler Units (HDUs).
FEATURES
SPECIFICATIONS
INSTALLATION
To ensure proper installation of the HLU-231:
1Align the HLU with the shelf rails and slide the unit in.
2When the HLU is properly seated, the retaining latch on the HLU snaps closed.
POWER-UP SEQUENCE
When the HLU powers up, the four-character display illuminates and reports status messages.
If the HLU is not communicating with the next span device, the following occurs:
1Alarm and diagnostic messages are displayed (see the Front Panel Alarm Messages and Front Panel Diagnostic Messages
tables inside), followed by the SELF TEST message.
2The Status LED turns yellow, indicating it has entered self-test mode.
•Front panel status LED, four-character status
display, and RS-232 craft port
•Payload (PL) or HiGain (HG) loopback source
identification
•Five-span range with four doublers
(60 kft, 24 AWG)
•Low line-power option (-140 V) for circuits
with a single doubler
•Selectable Power Feed modes •Bit Error Rate (BER) alarm options
•Loss of Signal (LOS)/Alarm Indicator signal
(AIS) payload alarm option
•Bipolar Violation Transparency (BPVT)
options
•Customer Disconnect Indicator (CDI) •Digital Data Service (DDS) latching loopback
•Additional screens for inventory and
troubleshooting •Grounded loop detection
Operating Temperature -40 °F to +149 °F (-40 °C to +65°C)
Operating Humidity 5% to 95% non-condensing
HDSL Span Voltage -140 to ±112 Vdc
Mounting 220 mechanics
HDSL Line Code 784 kbps 2B1Q
HDSL Output +13.5 dBm ±0.5 dB at 135 Ω
Maximum Provisioning Loss 35 dB at 196 KHz, 135 Ω
DS1 Line Rate 1.544 Mbps ±200 bps
DS1 Line Format
Alternate Mark Inversion (AMI), Bipolar with
8-Zero Substitution (B8ZS) or Zero Byte Time
Slot Interchange (ZBTSI)
DS1 Frame Format Extended SuperFrame (ESF), SuperFrame (SF) or
Unframed (UNFR)
DSX-1 Pulse Output 6 V pk-pk, pre-equalized for 0 - 655 feet of ABAM cable
DSX-1 Input Level +1.5 to -7.5 dB DSX

HLU-231 List 8E Technical Practice 3
If the HLU is communicating with the next span device, the following occurs:
1The Status LED flashes green while acquiring each device in the system, and turns a steady green when the entire system
is operating without any alarms.
2The four-character display reports margin (signal-to-noise ratio) readings and insertion loss.
3If the status LED is not solid green, the display reports alarm conditions (see the Front Panel Alarm Messages table
inside).
PROVISIONING
1Access the Maintenance Terminal screens by pressing the several times.
aSet the date and time (select Set Clock from the Main Menu).
bSet the circuit IDs (select View System Inventory).
2Access the Systems Settings selection on the Main Menu to change the default settings of any system parameters.
3Access the View Troubleshooting screen to view a graphical analysis of any potential system problems.
When the HLU has been successfully installed and provisioned, clear Span Status, Performance Data, Performance History,
and Alarm History screens to ensure accurate data and alarm reporting.
63$&(%$5

4 HLU-231 List 8E Technical Practice

HLU-231 List 8E Technical Practice 5
LOOPBACK TESTING
Initiate loopback testing from the HiGain maintenance menus or use the MODE and SEL buttons. The hexadecimal inband
codes shown below can also be sent by a test set.
GNLB Loopback Commands
Loopback Inband Code Description
NLOC 1111000 DSX-1 signal is looped back to DSX-1 at HLU.
NDU1 110000 Query to initiate loopback at doubler 1 to the network.
NDU2 111000 Query to initiate loopback at doubler 2 to the network.
NDU3 1010001 Query to initiate loopback at doubler 3 to the network.
NDU4 1010010 Query to initiate loopback at doubler 4 to the network.
NREM 1110000 DSX-1 signal is looped back to DSX-1 at the HRU.
SMJK 11000 DSX-1 signal is looped back to DSX-1 at the HRU SmartJack
module.
CLOC 1111100 Signal from customer is looped back to the customer at the HRU.
CDU1 111100 Query to initiate loopback at doubler 1 to the customer premises.
CDU2 111110 Query to initiate loopback at doubler 2 to the customer premises.
CDU3 1011001 Query to initiate loopback at doubler 3 to the customer premises.
CDU4 1011010 Query to initiate loopback at doubler 4 to the customer premises.
CREM 1111100 Signal from customer is looped back to the customer at the HLU.
Loopdown 11100 Deactivates any of the above loopback commands.
For more detailed information about the Maintenance Terminal screens, provisioning, and
loopback mode testing, refer to the HLU-231 List 8E technical practice, document number
150-231-185-xx. It can be downloaded from the Customer site portion of the PairGain Web
page at
www.pairgain.com
. A password is required to access the Customer site web pages.
If you do not have a password, contact your PairGain sales representative.
Front Panel Alarm Messages(a)
(a) ALRM displays prior to any alarm message. Pressing the SEL button initiates an Alarm Cutoff (ACO)
message.
Message Description
LOSW One of the HDSL loops has lost sync.
LLOS No signal is detected at the DSX-1 input to the HLU.
RLOS No signal is detected at the DS1 input to the HRU.
BER A system Bit Error Rate alarm is in effect.
MAL1 or MAL2 The margin on HDSL Loop 1 or 2 has dropped below the threshold (1 to 15 dB) setting.
NONE No alarm present.

6 HLU-231 List 8E Technical Practice
System Configuration Codes(a)
Code Description
VER xxxx The release revision of the firmware (appears during the System Settings review mode).
LIST xxxx The model number of the product (appears during the System Settings review mode).
FRM xxxx Indicates the type of frame pattern being received from the DSX-1, where xxxx is SF,
ESF, UNFR, or NONE).
CODE xxxx The line code setting, where xxxx is AMI or B8ZS.
PLEV xxxx Indicates the HDSL line voltage in its LOW (-140 Vdc), HIGH (±112 Vdc) state, or DIS
(disabled) state.
(a) To view system configuration codes, press the MODE button for 3 or more seconds.
Front Panel Diagnostic Messages
Message Description (normal operating messages in bold)
1=xx or 2=yy 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 The multiplexers of the HLU and the HRU or the first doubler are trying to establish
synchronization over Loop 1 or Loop 2 of Span 1.
AnL1 or AnL2 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? The HLU is not receiving any response from the HRU.
DS0 NONE = no DS0 channels blocked. BLK = some channels blocked.
FERR Framing bit error occurred at HLU T1 input.
FRM Defines the type of frame pattern being received from the DSX-1.
H1ES or H2ES HDSL Loop 1 or Loop 2 CRC error.
nHDU Number (n) of doublers in the circuit.
INSL xxDB The maximum Insertion Loss message (INSL) appears followed by xxDB, where xx is the
maximum insertion in dB of all spans and loops.
LBPV A bipolar violation has been received at the T1 input to the HLU-231.
MNGD The HLU is under control of the HMU-319 Network management unit.
PWR FEED GND One of the HDSL loops has been grounded.
PWR FEED ON Indicates that the HDSL loops are not grounded or shorted.
PWR FEED OFF HDSL span power has been turned off.
PWR FEED SHRT Indicates a short between the two HDSL pairs or the inability of the HRU to communicate
with the HLU.
SELF TEST The HLU is in a self-test mode. This occurs every power on/off cycle.
SIG1 or SIG2 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 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.
TLOS HRU is in logic loopback mode caused by loss of its T1 input from the CI.

HLU-231 List 8E Technical Practice 7
System Settings
Display Code Description (default values in bold)
EQL Sets the DSX-1 Equalizer to:
EXT (replaces the Internal Equalizer with an External Equalizer), 0 (0 to 133 ft.),
133 (133 to 266 ft.), 266 (266 to 399 ft.), 399 (399 to 533 ft.), 533 (533 to 655 ft.).
LBPK Enables (ENA) or disables (DIS) all inband SMJK loopback commands. ENFT enables response
to Digital Data Service latching loopback commands requiredfor fractional T1 applications. The
Customer Disconnect Indicator (CDI) option is disabled when ENFT is selected.
SPLB Configures the system for generic inband loopback commands (GNLB) or special
loopback commands (A1LB/A2LB, A3LB, A4LB, A5LB).
PWRF DIS = disables HDSL powering; LOW = HDSL line voltage is -140 V max.;
AUTO = automatically switches between -140 V for nondoubler applications and ±112 V
for doubler applications); HIGH = ±112 V for all applications.
ZBTS ON = ESF frame is operating in ZBTSI mode.
OFF = ESF frame is operating in non-ZBTSI mode.
BERT NONE = prevents generation of a system alarm due to excessive BER
1E-6 or 1E-7 = alarm activates when BER threshold exceeds 10-6 or 10-7.
LBTO Loopback timeout = NONE, 20, 60, 120.
ALM System alarms enabled (ENA) or disabled (DIS) on pins 20-21.
DS1 Line code = AUTO, B8ZS, or AMI.
FRMG Framing = AUTO or UNFR (unframed).
HAIS Transmits the AIS signal at the HLU and HRU output ports if one (1LP) or both (2LP)
HDSL loops are not in sync.
SAIS Enables (ENA) or disables (DIS) SMJK loopback mode.
DS0 DS0 blocking on (BLK) or off (NONE); can only be set through the craft port.
MARG 0 to 15 dB; the default is 4dB; can only be set through the craft port.
RDA Enables (ENA) or disables (DIS) remote DS1 LOS at HRU input.
ALMP Enable line to output an (AIS) payload or an (LOS) condition.
RTPV Enables (ENA) or disables (DIS) remote provisioning from the HRU. PWRF and RTPV
cannot be set from the HRU.
BPVT Enables (ENA) or disables (DIS) BPV transparency.
CDI Customer Disconnect Indicator enables (ENA) the HLU to send special patterns that
indicate an RLOS condition, or disables (DIS) the CDI patterns.
CONF Update all operating mode selections (YES or NO).

8 HLU-231 List 8E Technical Practice
FCC Certification
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, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the
interference at his own expense.
Limited Warranty
PairGain Technologies warrants this product to be free of defects and to be fully functional for a period of 120 months from the date of original shipment, given
correct customer installation and regular maintenance. PairGain will repair or replace at PairGain’s option any unit without cost during this period if the unit is
found to be defective for any reason other than abuse or incorrect use or installation.
Do not try to repair the unit. If it fails, replace it with another unit and return the faulty unit to PairGain for repair. Any modifications of the unit by anyone other
than an authorized PairGain representative voids the warranty.
If a unit needs repair, call PairGain for a Return Material Authorization (RMA) number and return the defective unit, freight prepaid, along with a brief description
of the problem.
PairGain continues to repair faulty modules beyond the warranty program at a nominal charge. Contact your PairGain sales representative for details and pricing.
Modifications
Any changes or modifications made to this device that are not expressly approved by PairGain Technologies, Inc. may void the user's warranty.
All wiring external to the products should follow the provisions of the current edition of the National Electrical Code.
Standards Compliance
The HLU-231 List 8E has been tested and verified to comply with the applicable sections of the following standards.
❑GR 63-CORE - Network Equipment-Building System (NEBS) Requirements: Physical Protection
❑GR 1089-CORE - Electromagnetic Compatibility and Electrical Safety
Trademark Information
PairGain and HiGain are registered trademarks of PairGain Technologies, Inc. All other product names mentioned in this installation guide are used for
identification purposes only and may be trademarks or registered trademarks of their respective companies.
Copyright Information
©Copyright 1999 PairGain Technologies, Inc.
Information contained in this document is company private to PairGain Technologies, Inc., and shall not be modified, used, copied, reproduced or disclosed in
whole or in part without the written consent of PairGain Technologies, Inc.
Corporate Office:
14402 Franklin Avenue
Tustin, CA 92780
Tel: [phone]
FAX: [phone]
For Technical Assistance:
[phone]
Product Number: 150-1111-85
CLEI Code: T1L2F10A
Section Number: 350-231-185-05
August 10, 1999