PairGain ELU-319 User manual

PAIRGAIN TECHNOLOGIES Section 150-319-254
Technical Practice Revision 02
Engineering - PLANT Series February 22, 1996
Page 1
PAIRGAIN TECHNOLOGIES HIGAIN™LINE UNIT
MODEL ELU-319
List 5D, PairGain #150-1236-54 (75 Ohm)
List 6D, PairGain #150-1236-64 (120 Ohm)
CONTENTS PAGE
A. GENERAL 2
1. INTRODUCTION 2
2. APPLICATIONS 3
3. FUNCTIONAL OPERATION 3
4. ALARMS 5
5. OPTIONS 8
6. HDSL LINE VOLTAGE OPTION 9
7. INSTALLATION 10
8. SPECIFICATIONS 10
9. CERTIFICATION 11
10. WARRANTY 11
11. TECHNICAL ASSISTANCE 11
B. APPLICATIONS WITHOUT USING HIGAIN
DOUBLER EDU-451 11
1. GENERAL 11
2. POWER CONSUMPTION 11
3. LOOPBACK DESIGN DESCRIPTION 12
4. TESTING 13
5. SYSTEM MAINTENANCE MENU
SCREENS 17
C. APPLICATIONS USING HIGAIN DOUBLER
EDU-451 23
1. GENERAL 23
2. POWER CONSUMPTION 23
3. LOOPBACK DESIGN DESCRIPTION 24
4. TESTING PROCEDURES 26
5. SYSTEM MAINTENANCE MENU
SCREENS 30
CAUTION
This product incorporates static sensitive
components. Proper electrostatic discharge
procedures must be followed.
Figure 1. ELU-319, List 5D and 6D Front Panel. The
PairGain ELU-319, List 5D and 6D can be used in
conjunction with the ERU-412 remote unit and either one
or two EDU-451 doubler units to provide a complete
HiGain HDSL system over extended distances.

Section 150-319-254
Revision 02
Page 2
A. GENERAL
1. INTRODUCTION
1.01 PairGain's HiGain Line Units Model ELU-
319, Lists 5D and 6D (Figure 1), are the
Public Exchange side of a repeaterless G.703
transmission system. When used with an ERU-412
HiGain Remote Unit (ERU), the system provides
2.048 Mbps transmission on two unconditioned
copper pairs. The “D” designation in the list number
indicates that this line unit can be used in doubler
applications to line power one doubler and one ERU
remote unit or two doublers. This is in contrast to
the ELU-319 List 5 and 6 which can only line power
one doubler or one ERU remote unit. The HiGain
system uses HDSL (High-bit-rate Digital Subscriber
Line) transmission technology as recommended by
Bellcore TA-TSY-001210. HiGain complies with TR-
TSY-000063 (Network Equipment Building System
(NEBS) Generic Equipment requirements) and TR-
TSY-000499 (Transport System Generic
Requirements–TSGR) common requirements.
1.02 Revision History of this practice.
Revision 02—February 22, 1996
a) Numerous updates to tables, figures,
also screen captures to include HiGain
Doubler EDU-451.
1.03 The ELU-319 is compatible with the
PairGain 22-slot HMS-318 shelf and the
associated G.703 HiGain connector panel HCP-322.
1.04 ELU-319 Product Family:
• List 5D: 75-ohm G.703 Impedance
• List 6D: 120-ohm G.703 Impedance
1.05 ELU-319 Issue 1 features:
• -130V dc or -200V dc line power for
ERU-412 or EDU-451
•• Optimal symmetric or ?symmetric HDSL
line voltage
• Four-digit front panel display for HDSL
signal/noise (S/N) margin, configuration,
and alarms
• RS-232 maintenance port
• Non-volatile configuration memory
• Front panel splitting and bridging access to
G.703 interface
• Lightning and power cross protection on
HDSL interfaces
• 1040 kbps full-duplex two-bits one-
quaternary (2B1Q) HDSL transmission on
each of two pairs
• Front panel status-indicating light-emitting
diode (LED) indicator
• On / Off front-panel display power cycling
• G.703 Loss of Signal (LOS) detector (125
consecutive zeros)
• Margin threshold alarm
• Single step default setting option
• Circuit ID option
• Improved tolerance to cable noise
• Line powers two EDU-451 doublers or one
EDU and ERU.

Section 150-319-254
Revision 02
Page 3
TABLE 1. HDSL CABLE LOSS
Cable Gauge Loss @ 260 kHz(db/km) Ohms per km
26/0.4 mm 13.94 272
24/0.51 mm 10.47 171
22/0.61 mm 8.14 105
19/0.91 mm 5.74 52
TABLE 2. HIGAIN E1 RANGES (KM) ON
UNIMPAIRED CABLES VS AVERAGE
MARGIN(M) IN DB
Cable Gauge M = 11 M = 7 M = 3
0.4 mm / #26 AWG 2.7 km 3.0 km 3.3 km
0.51 mm / #24
AWG 3.6 km 4.0 km 4.4 km
0.61 mm / #22
AWG 4.7 km 5.2 km 5.7 km
0.81 mm / #19
AWG 6.6 km 7.3 km 8.0 km
2. APPLICATIONS
2.01 The HiGain System provides a cost-
effective, easy-to-deploy method for
delivering G.703 High Capacity Digital Service
(HCDS) over metallic pairs. The fiber-like quality
service is deployed over two unconditioned, non-
loaded copper pairs. Conventional span repeaters
are not required. Cable pair conditioning, pair
separation and bridged tap removal, are also not
required.
2.02 The HiGain system operates with any
number of other G.703, Plain Old Telephone
System (POTS), digital or analog data service or
other HiGain Systems sharing the same cable
binder group. HiGain provides a means of quickly
deploying service in advance of fiber-optic
transmission systems. By using HiGain G.703, you
can connect service within a few days or even a few
hours. You can install fiber optic systems at a
leisurely pace and cut-over from HiGain when the
time allows. You can then easily remove the HiGain
and utilize it elsewhere.
2.03 Table 1 provides a guide for the loss of
various cable gauges at the HDSL line rate
of 260 kHz and 135 ohms. The table applies to the
HDSL cable pairs between the ELU and the EDU-
451 as well as between the EDU-451 and a second
EDU-451 or the ERU-412. Add 3 dB for each
bridged tap and 1 dB for each cable gauge change.
2.04 The ELU to ERU operating ranges, on
unimpaired cable pairs, are shown in Table
2 as a function of cable gauge and average margin.
2.05 The ELU-319, List 5D and 6D line units
support both one and two doubler
applications. For two doubler applications the ERU
must be locally powered. For one doubler
applications both the EDU and ERU can be line
powered.
3. FUNCTIONAL OPERATION
3.01 HiGain utilizes PairGain's 2-Bits-1-
Quaternary (2B1Q) HDSL transceiver
systems to establish two full-duplex 1040 Kbps data
channels between the ELU-319 and an ERU-412
HiGain Remote Unit or EDU-451 doubler unit. This
provides a total capacity of 2.080 Mbps between the
two units: 2.048 Mbps for the G.703 interface and 32
Kbps of overhead.
3.02 A block diagram of the ELU-319 is shown in
Figure 2. The HiGain ELU-319 receives a
2.048 Mbps data stream from the G.703 digital
cross-connect interface.
3.03 The ELU-319 contains a demultiplexer that
generates two parallel 1040 kbps data
streams. Each data stream consists of HDSL
frames that are nominally 4704 bits (4.5
milliseconds) in length. Each frame contains a 14-
bit Frame Sync Word (FSW), a 6-bit Cyclic
Redundancy Check (CRC), a 21-bit operations
channel and 16 of the 32 G.703 timeslots. The
demultiplexer provides frame synchronization for
each of the two HDSL channels. The multiplexer
and HDSL transceivers work under control of the
ELU-319 microprocessor and compensate for data
inversions caused by tip-ring reversals and for
channel swaps caused by pair reversals. The
HiGain system tolerates tip-ring reversals, HDSL
cable pair reversals but does not tolerate split pairs.
3.04 The two formatted HDSL channels pass to
the HDSL transceivers, which convert them
to 2B1Q format. The 2B1Q line code operates in
full-duplex mode on unconditioned pairs. The
transceiver's digital echo cancelers and adaptive
equalizers receive the signal from the remote end in
the presence of impairments and noise on the

Section 150-319-254
Revision 02
Page 4
copper pairs. Each of the two HDSL channels
contain 16 G.703 timeslots3.05 The transceiver
processes the HDSL channels it receives and
passes them on to the ELU-319 multiplexer. The
multiplexer removes data link messages from the
HDSL channels and passes them to the
microprocessor. This enables the ELU-319 and the
ERU-412 Remote Unit to exchange operations
messages and status. By synchronizing to the FSW
of each channel, the multiplexer can reconstruct the
original 2.048 Mbps G.703 stream from the payloads
of the two HDSL channels. The CRC fields on the
HDSL streams enable the ELU-319 to determine if
errors are present on the channel due to excessive
impairments caused by impulse or crosstalk noise.
3.06 The reconstructed HDSL data channel is
buffered in a first-in-first-out (FIFO) buffer
within the multiplexer. A frequency synthesizer in
conjunction with the buffer regulates the output bit
rate and reconstructs the G.703 clock at the exact
rate received from the remote end. The HiGain
system operates at G.703 rates of 2.048 Mbps with
up to ±50 ppm of offset.
3.07 A G.703 interface driver converts the G.703
channel to a High Density Bipolar 3 (HDB3)
format.
3.08 The transmit and receive G.703 ports have
splitting access and bridging “Bantam”-type
jacks. Connecting one cable between the two BDG
jacks and another between the two LINE jacks splits
the XMT and RCV, creating metallic loopbacks
towards the customer equipment and HDSL line.
3.09 The ELU-319 contains two separate power
converters. The main power supply
converts -48V local battery to logic power for the
ELU-319 circuits. The line power supply converts
the -48V battery to either -130V for non-doubler
applications or -200V for doubler applications there
provides simplex power feed on the HDSL loops.
The line power can be turned on or off by the
microprocessor and automatically shuts down in the
presence of line short-circuits or microprocessor
failure.
Figure 2. ELU-319 Block Diagram. PairGain’s HDSL technology provides full-duplex services at 2.048 Mbps over copper
wires between an ELU-319 and an ERU-412 or EDU-451.

Section 150-319-254
Revision 02
Page 5
4. ALARMS
4.01 An RS-232 connector (DB-9) on the front
panel provides access to HiGain
maintenance, provisioning and performance
monitoring interface. Basic functionality is available
via a 'dumb terminal'. For ‘dumb terminal’ operation
procedures, refer to Sections A.5.07 through A.5.11,
B.3, and C.3.
4.02 Pin H of the ELU-319 is the minor alarm
(MNRALM) output pin. This pin must never
operate above 0V or below -60V. The ELU-319
forces pin H to ground (maximum of 10 mA) for any
of the conditions listed below, with the
accompanying front panel message in bold letters.
More than one alarm condition can exist at any
given time, but the unit can display only one
message. For multiple alarms, only the highest
priority alarm appears. The alarms are listed in their
order of priority:
1) ALRM LOSW: Loss of synchronization in
either HDSL loop.
2) ALRM LLOS: Loss of ELU-319 G.703
input signal.
3) ALRM RLOS: Loss of ERU-412 G.703
input signal.
4) ALRM H1ES: An HDSL Loop 1
transceiver has exceeded the 24-hour
user-selected Errored-Seconds
threshold.
5) ALRM H2ES: An HDSL Loop 2
transceiver has exceeded the 24-hour
user-selected Errored-Seconds
threshold.
6) ALRM G.703: The total number of
bipolar violations (BPV) at the ELU or
ERU G.703 inputs exceeded the 24-hour
user-selected threshold.
7) ALRM MAL1 (2): The margin on HDSL
Loop 1 (Loop 2) has dropped below the
Margin Alarm Threshold value set from
the Maintenance Port menu.
4.03 Pin H (Figure 3) (MNRALM) of the ELU-319
remains grounded for the duration of the
alarm condition. The ELU-319 STATUS LED
flashes red for the duration of a minor alarm
condition. You can retire the MNALRM by pressing
the front panel SEL(ect) button, thus executing the
alarm cut-off (ACO) option. This turns the alarm off
and replaces the ALRM message with ACO. The
part of the message that defines the alarm remains
until the alarm condition clears or another alarm
occurs. Disabling the ALM also retires an ACO
condition.
4.04 Setting the ALM option to DIS(able) only
pre- vents the unit from activating the MNRALM
output alarm bus on pin H on a minor alarm event.
The STATUS LED still flashes red and the ALRM
message still appears.
4.05 The ELU-319 drives pin 10 (FUSEALARM)
to -48V whenever its on-board fuse opens.
Its normally floating output must never operate
above ground or below -80V. It can sink a current of
10 mA.
4.06 The ELU-319 Line Unit front panel tri-color
STATUS LED has the following states:
• GREEN - Normal operation
• FLASHING GREEN - HDSL acquisition
• FLASHING RED - MNRALRM (For all
alarm conditions)
• RED - FUSEALRM
• YELLOW - Self-test in progress or an
ELU-319 loopback in effect (CREM or
Network Local Loopback (NLOC))

Section 150-319-254
Revision 02
Page 6
Figure 3. ELU-319 Pin-Outs. The active pins are
highlighted in black in this illustration.

Section 150-319-254
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Page 7
TABLE 3. SYSTEM PARAMETER OPTION SETTINGS
Parameter Option Description
PWRF (Power Feed) DIS Disables powering to the ERU over the HDSL pairs.
ENA* Enables powering to the ERU over the HDSL pairs.
ESAL (Errored Seconds Alarm
Threshold) 17 Activates MNRALM (on pin H) after 17 Errored Seconds (17 HDSL CRC errors on either HDSL loop or a total of 17 BPVs and FERR) occur
within 24 hours.
170 Activates MNRALM (on pin H) when 170 Errored Seconds occur within
24 hours.
NONE* Prevents generation of a minor alarm due to excessive Errored
Seconds.
LBTO (Loopback Timeout) NONE Disables automatic time-out cancellation of all loopbacks.
20 Sets automatic cancellation of all loopbacks to 20 minutes after
initiation.
60* Sets automatic cancellation of all loopbacks to 60 minutes after
initiation.
120 Sets automatic cancellation of all loopbacks to 120 minutes after
initiation.
ALM (Minor Alarm) DIS* Retires an existing minor alarm on pin H by disabling its signal, and
prevents another minor alarm from occurring.
ENA Enables pin H to be grounded when a minor alarm condition occurs.
CONF (Confirm) YES Confirms that all 4 operating modes are to be updated to their current
choices.
NO* Prevents the most recently selected operating mode choices from being
updated. They remain as they were prior to entry of system option
settings procedure.
MARG (Margin Alarm
Threshold) 0 to 15
4*
Displays the Margin Alarm Threshold (in dB),that is set using the RS-
232 Maintenance port. If the margin on either loop drops below this
value, a minor alarm is reported (MAL1 or MAL2). The factory Default
is 4.
* Indicates the ELU-319 factory settings.

Section 150-319-254
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Page 8
5. OPTIONS
5.01 The operating mode of the ELU-319
depends on the settings of the following
system operating parameters:
• PWRF—Power Feed (HDSL line power)
• ESAL—Errored Seconds Alarm Threshold
• LBTO—Loopback Timeout
• ALM—Minor Alarm
• MARG—Margin Alarm Threshold
5.02 Table 3 lists the ELU-319 system
parameters and their optional settings. The
ELU-319 stores the settings of the system parameters
in non-volatile RAM to prevent their loss in the event
that shelf power is lost or the ELU-319 is unplugged.
5.03 No DIP-switches or jumpers are required to
set the ELU-319 configuration. You can set
all the system parameter options with the front panel
pushbuttons (MODE and SEL) except the MARG
threshold. The latter can be set from the maintenance
terminal through the ELU-319 RS-232 interface.
5.04 To initiate the Option Set mode from the
ELU-319 front panel, press and hold the
MODE button for one second. The front panel
message alternates between the system parameter
and its current setting. Press the SEL button to step
through all possible values (in sequence) of the
parameter being displayed. Press MODE when the
desired setting is displayed. This selects the next
configurable parameter. When you have selected the
last parameter, the display displays “CONF/NO”. To
return to original settings, press the MODE button. To
accept the new settings, press the SEL button. This
displays “CONF/YES”, installs the changes, and
returns to normal display mode. If you do not press
either button within 30 seconds, the parameters return
to their original values, and the display returns to
normal mode.
5.05 To set all parameters to their default values,
press and hold the SEL button for six or more
seconds. The message “DFLT/NO” appears when
you release the button. Press SEL again to display
“DFLT/YES” and accept the default values. Press
MODE to cancel and return to the original values.
5.06 Press the MODE button for 3 or more
seconds to scroll through the ELU-319
software version number, List #, and all parameter
option settings.
Figure 4. ELU-319 DB-9 Pin-Outs. A standard RS-232
(DB-9) connector on the front panel provides access to the
menu interface feature via a dumb terminal.
5.07 To configure the ELU-319 from the
Maintenance port, connect an ASCII display
terminal to the RS-232 Maintenance port with a cable
configured as shown in Figure 4. The maintenance
port is configured as Data Communications
Equipment (DCE) with 8 data bits, 1 stop bit and no
parity. Striking the SPACE bar several times invokes
the “autobaud” function over a range of 1200 to 9600
bps.
5.08 The menus and informational screens
displayed by the terminal are shown in
Figures 6 through 13 for non-doubler applications.
Figures 15 through 31 show the screens for doubler
applications. From the Main Menu (Figure 6 or 15),
select C–SYSTEM SETTINGS. Entering the letter in
parenthesis of the parameter you want to change
scrolls the parameter through its options. When you
have made the new settings, enter C to confirm.
5.09 Two user settings, Circuit ID, and Margin
Alarm Threshold, must be set from the display
terminal.

Section 150-319-254
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Page 9
5.10 To set the Circuit ID, select H from the Main
Menu to display “Enter circuit ID # (24
characters max)”. Enter the circuit ID, press ENTER,
then press C to confirm the entry. If you enter more
than 24 characters, the terminal beeps and accepts
only the first 24 characters. The circuit ID appears in
all screens, and you cannot reset it to a default as
described in Paragraph 5.05.
5.11 To set the Margin Alarm Threshold, select
G–SYSTEM SETTINGS and then select G–
MAR(G)IN ALM THRES. Enter the minimum
acceptable alarm threshold, from 0 to 15 dB. If the
margin for HDSL Loop 1 or 2 drops
below this value
,
the ELU-319 triggers a minor alarm, and the front
panel and status screen displays “MAL1” (Loop 1) or
“MAL2” (Loop 2). Because a margin can never be
less than zero, setting a threshold of zero turns this
feature off.
6. HDSL LINE VOLTAGE OPTION
6.01
The symmetry of the HDSL line powering voltage
can be set by the S2 switch, located on the printed
circuit board, as shown in Figure 5.
6.02
The factory default setting is unipolar (-). It sets
the HDSL line voltage to 0 V on loop 2 and to
either -130 V (for non-doubler applications) or -200 V (for
doubler applications) on loop 1. This setting keeps the
HDSL cable pair voltage at or below ground potential,
thereby avoiding corrosion problems caused by cable
voltages more positive than ground.
6.03
The bipolar selection sets the HDSL line voltage
to +65 V on loop 2 and -65 V on loop 1, for non-
doubler applications. Doubler applications will have +100
V on loop 2 and -100 V on loop 1. This setting reduces the
maximum ground referenced voltage to 100 V, but applies
positive voltage to the cable pairs, which could accelerate
corrosion on the cable pairs.
6.04
The line voltage power supply, used for both
options, is ground referenced, but also ground
isolated by 200 kohms. This ground isolation reduces
problems due to induced noise currents and large surge
voltages, which are ground referenced. It also reduces
ground fault currents, which improves the products safety.
The safety issue thus depends solely on the differential
voltage across loop 1 and loop 2, and is independent of
S2s setting.

Section 150-319-254
Revision 02
Page 10
Figure 5. HDSL Line Voltage
Switch S2
7. INSTALLATION
7.01 Upon receipt of equipment, visually
inspect it 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.
7.02 The ELU-319 mounts in the PairGain
HMS-318 shelf. The auxiliary PairGain
connector panel, HCP-322, connects to the HMS-
318 shelf and provides G.703, BNC connector
access (75 ohm or 120 ohm) to each of the 22 slots.
The ELU-319 slot pin-outs are shown in Figure 3.
8. SPECIFICATIONS
HDSL Line Code
1040 kbps, 2B1Q
HDSL Output
+13.5 dBm ± 0.5 dB @ 135 ohms
HDSL Line Impedance
135 ohms
Line Clock Rate
Internal Stratum 4 clock
HDSL Startup Time
30 seconds (typical), 60 seconds (maximum)
One-way G.703 Delay
Less than 220 microseconds
G.703 Line Impedance
List 5D: 75 ohms
List 6D: 120 ohms
G.703 Input Level
+1.5 to -7.5 dB
G.703 Line Rate
2.048 Mbps ± 200 bps
G.703 Line Format
HDB3
Power Consumption
12 watts (no doubler), 21 watts (doublers)
Heat Dissipation
6 watts (no doubler), 8 watts (doublers)
Fusing
Internal, 1.25 A at 125 V, connected to
FUSEALARM output on pin 10
Span Voltage
-130V dc or 200V dc
Margin Indicator
Displays loop SNR margin for both loops relative
to 10-7 BER operation
Electrical Protection
Secondary surge protection on G.703 and HDSL
ports
Power cross protection on HDSL ports

Section 150-319-254
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Page 11
Operating Temperature and Humidity
-40° to 65° Celsius, 5% to 95% (non-condensing)
Mounting
HMS-318 shelf with HCP-322 connector panel
Dimensions
Height: 4.75 in. (12.07 cm)
Width: 0.7 in. (1.78 cm)
Depth: 10.5 in. (26.67 cm)
9. CERTIFICATION
9.01 FCC compliance: The ELU-319 has been
tested and found to comply with the limits
for Class A digital devices 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.
10. WARRANTY
10.01 PairGain Technologies warrants this product
to be free of defects and to be fully
functional for a period of 36 months from the date of
original shipment, given proper installation. PairGain
will repair or replace any unit without cost during this
period if the unit is found to be defective for any
reason other than abuse or improper use or
installation.
10.02 This module should not be field repaired. 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.
10.03 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, to:
PairGain Technologies, Inc.
14402 Franklin Avenue
Tustin, CA 92680
ATTN: Repair and Return Dept.
[phone]
[phone]
11. TECHNICAL ASSISTANCE
11.01 PairGain Technical Assistance is available
24-hours-a-day, 7-days-a-week by
contracting PairGain’s Customer Service
Engineering group at one of the following numbers:
Telephone: [phone] or [phone]
Fax: [phone]
During normal business hours (8:00 AM to 5:00 PM,
Pacific Time, Monday - Friday, excluding holidays),
technical assistance calls are answered directly by a
Customer Service Engineer. At other times, a
request for technical assistance is handled by an on-
duty Customer Service Engineer through a callback
process. This process results in a callback within 30
minutes of initiating the request. In addition,
PairGain maintains a computer bulletin board
system for obtaining current information on PairGain
products, product troubleshooting tips and aids,
accessing helpful utilities, and for posting requests
or questions. This system is available 24-hours-a-
day by calling [phone]. Transmission
speeds up to 28.8 kbps are supported with a
character format of 8-N-1.
B. APPLICATIONS WITHOUT USING HIGAIN
DOUBLER EDU-451
1. GENERAL
1.01 This section addresses ELU-319 List 5D
and 6D operation when used without
doublers. For applications without Doublers, the
ELU is directly connected to the ERU-412 by the two
cable pairs.
2. POWER CONSUMPTION
2.01 The three most important power demands of
an ELU-319 on the shelf power supply are
its maximum power consumption, its maximum
power dissipation and its maximum current drain.
These three parameters for the ELU-319 on a per
slot and per shelf basis, are as follows:
Maximum Power Dissipation:
• Per Slot = 6 Watts
• Per Shelf = 132 Watts
Maximum Power Consumption:
• Per Slot = 12 Watts
• Per Shelf = 264 Watts

Section 150-319-254
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Page 12
Maximum Current Drain:
• Per Slot = 0.28 A
• Per Shelf = 6.2 A
Note that the worst case conditions under which
these parameters were measured include a 3.3 km,
0.4 mm loop, a fully loaded 22-slot shelf and a -42.5
V shelf battery voltage.
2.02 The Maximum Power Dissipation measures
the power that is converted into heat build
up within the unit. It contributes to the total heat
generated in the space around the unit. It is used to
determine the maximum number of fully loaded
shelves per bay that does not exceed the maximum
allowable power dissipation density in Watts/sq. ft.
2.03 The thermal loading limitations imposed
when using the ELU-319 in Controlled
Environmental Vault (CEV) or other enclosures are
determined by applying the ELU-319 power
parameters to the manufacturer's requirements for
each specific housing.
2.04 The Maximum Power Consumption is the
total power that the ELU-319 consumes or
draws from its -48 V shelf power source. This
parameter is needed when the 319 is located remote
to its serving CO. It determines the battery capacity
required to maintain an 8-hour stand-by battery
reserve for emergency situations. It thus limits the
maximum number of plugs per remote enclosure.
Use the above data to perform this analysis on a
case by case basis.
2.05 The Maximum Current Drain is the
maximum current drawn from the shelf power
supply when it is at its minimum voltage (-42.5 V).
This determines the shelf fusing requirements. The
PairGain HMS-318 and 317 ELU-319 shelves are
partitioned into two equal halves; each should be
fused at 10 A for a total of 20 A per shelf. A fully
loaded shelf draws 6.2 A worse case. This is within
the 10 A fuse limit.
3. LOOPBACK DESIGN DESCRIPTION
3.01 All HiGain ELU/ERU system loop-up codes
must be initiated from either the front panel
pushbuttons or from the maintenance terminal. The
HiGain E1 system does not respond to any
in-band
codes
.
3.02 Depressing both the MODE and SEL
pushbuttons on the front panel for at least
three seconds initiates a MANUAL loopback
session. This session allows the user to SEL one of
four HiGain loopbacks (see Figure 5). The message
“MAN LPBK” appears on the front panel display
followed by the message “NLO?” If the SEL button
is now pressed, an NLOC loopback is executed and
the message changes from “NLO?” to “NLOC”. If
the MODE button is pressed instead of SEL button,
“NLO?” is replaced by “NRE?” If this same routine
is followed, all four loopbacks (NLOC, NREM,
CLOC, and CREM) are presented and can be
initiated in the sequence listed. Once a loopback is
executed, it can be terminated and the next
loopback option presented by pressing the MODE
button. If neither button is pressed for 30 seconds
and no loopback is in effect, this manual loopback
session terminates and the normal margin displays
reappear. If any loopback is in effect, this 30-
second time-out is inhibited. The active loopback
and the manual loopback session continue until the
loopback times out in accordance with the user
LBTO setting. Only one loopback may exist at any
given time. Depressing both buttons again for three
seconds terminates any active loopback, ends the
MANUAL loopback session, and returns the display
to normal.
3.03 Note that these same four loopbacks can be
initiated from the RS-232 maintenance port
by choosing LOOPBACK MODE, option D, from the
main menu. This displays the Loopback Menu,
shown in Figure 10, from which you can initiate any
of the four loopbacks.
3.04 The TLOS loopback (shown in Figure 5) is
controlled by a user switch option in the
ERU-412. When this option is enabled it forces the
ERU-412 into a logic loopback state when its G.703
input signal is lost. When this TLOS option is
disabled, no loop back occurs. When a LOS
condition exists the ELU-319 simply outputs the AIS
signal which alerts the network that a LOS condition
exists at the input to the ERL.
3.05 If the system should ever fail to respond to
any loopback command, go to the front
panel Option Setting mode and execute the
“DFLT/YES” command described in Section A,
paragraph 5.05. This will allow the system to
respond to the loopback commands. Reset the
parameters to their original non default values, if
needed, at your convenience, after the system
resumes its proper response to loopback
commands.

Section 150-319-254
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Figure 5. ELU-319 Loopback Configurations. All loopbacks (with the exception of the TLOS logic loopback) can be
initiated from the front panel pushbuttons or from the maintenance terminal.
4. TESTING
4.01 Table 4 lists the four-character front panel
message displays of the ELU-319. This
display energizes when power is initially applied to
the ELU-319; it indicates system status and error
conditions. In order to conserve power, the display
de-energizes after five minutes if neither MODE or
SEL are pressed. The use of either button restarts
the 5-minute power-control timer.
4.02 If you encounter trouble with the G.703
interface, verify that the unit is making a
positive connection with the mounting assembly's
connector.
4.03 The transmit and receive G.703 ports have
splitting access and bridging miniature 210-
type jacks as shown in Figure 2. Connecting one
cable between the two BRG jacks and another cable
between the two SPAN jacks splits the XMT and
RCV jacks and creates metallic loopbacks towards
both the G.703 cross connect and the ELU-319.

Section 150-319-254
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TABLE 4. ELU-319 FOUR-CHARACTER FRONT PANEL MESSAGES
Message Full Name Description
CREM Customer Remote Loopback Signal from customer is looped back to customer at ELU-319.
NLOC Network Local Loopback G.703 signal is looped back to G.703 at ELU-319.
CLOC Customer Local Loopback Signal from Customer is looped back to customer at ERU-412.
NREM Network Remote Loopback Network signal is looped back to network at the ERU-412.
TLOS Transmit Loss Of Signal ERU-412 is in a logic network loopback state caused by a loss
of its G.703 input at the ERU-412, if enabled via the ERU-412
TLOS switch option set to ON.
LBPV Local Bipolar Violation A bipolar violation has been received at the G.703 input to the
ELU-319.
SIG 1 or 2 Signal 1 or Signal 2 The ELU and ERU transceivers are trying to establish contact
with each other on Loops 1 or 2 of Span 1.
ACQ 1 or 2 Acquisition 1 or Acquisition 2 The ELU and ERU multiplexers are trying to establish
synchronization over each of Loops 1 or 2 of Span 1
H1ES HDSL Loop 1 errored second HDSL CRC error on Loop 1. Also displays when 24 hour ES
threshold has been exceeded.
H2ES HDSL Loop 2 Errored second HDSL CRC error on Loop 2. Also displays when 24 hour ES
threshold has been exceeded.
ACO Alarm CutOff An MNRALM has occurred, and was retired to an ACO condition
by pressing the SEL button on the ELU-319 front panel.
SELF TEST The ELU-319 is in a self test mode. This occurs every power ON
cycle. The self-test sequence includes the input G.703
transceiver chip when the HDSL loops are not in sync. This can
cause the AIS pattern, normally transmitted from the ELU during
this time, to exhibit bipolar violations (BPVs).
ALRM Alarm Condition Exists A minor alarm MNRALM condition is in effect.
1=xx
or
2=yy
HDSL Loop Margins Indicates the worst-case signal-to-noise ratio measured for each
loop. A value of ‘06’ or greater is adequate for reliable system
operation.
Table continued on next page

Section 150-319-254
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TABLE 4. ELU-319 FOUR-CHARACTER FRONT PANEL MESSAGES (CONTINUED)
PWR FEED
SHRT Power Feed Short Indicates a short-circuit between the two HDSL pairs, or the ERU-412 cannot communicate with the ELU-319 over good
cable.
PWR FEED
OPEN Power Feed Open Indicates an open circuit in the Tip and Ring of either HDSL pair.
BAD RT? No response from ERU The ELU-319 does not receive any response from the ERU-412.
Thus, the ERU’s integrity is questionable.
VER ELU Software Version # This is displayed during the System Settings review mode. Press
the Mode button for 3 seconds.
LIST 000X ELU’s List # Displayed during System Settings review mode defined above.
LOSW Loss of Sync Word Indicates that one of the HDSL loops has lost synchronization.
Causes a minor alarm.
LLOS Local Loss of Signal Indicates that no signal is detected at the G.703 input to the ELU-
319. Causes a minor alarm.
RLOS Remote Loss of Signal Indicates that no signal is detected at the G.703 input to the
ERU-412. Causes a minor alarm.
G.703 G.703 BPV errors Indicates that the number of BPVs at the ELU-319 or ERU-412
G.703 inputs have exceeded the 24-hour ES threshold. Causes
a minor alarm.
MAL1(2) Margin Alarm Loop 1 or 2 The margin on HDSL loop 1 (2) has dropped below the threshold
(1 to 15 dB) set by the user.

Section 150-319-254
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TABLE 5. ELU-319 STATUS MENU DEFINITIONS
Message Full Name Description
ALARMS
NONE No Alarms
LLOS Local Loss of Signal No signal from local G.703 interface.
RLOS Remote Loss of Signal No signal from remote G.703 interface.
LOSW 1 (2) Loss of (HDSL) Sync Word
1 or 2 HDSL LOOP 1 or 2 has lost frame sync.
H1ES HDSL Loop 1 Errored
Second The number of Loop 1’s Errored Seconds has exceeded the user- selected Errored Seconds threshold.
H2ES HDSL Loop 2 Errored
Second The number of Loop 2’s Errored Seconds has exceeded the user- selected Errored Seconds threshold.
G.703 G.703 G.703 input BPVs have exceeded the user selected ES threshold.
MAL1 Margin Alarm
(HDSL Loop 1) The margin on HDSL Loop 1 dropped below the Margin Alarm Threshold (1 to 15). Setting the threshold to 0 (zero) inhibits the
alarm.
MAL2 Margin Alarm
(HDSL Loop 2) The margin on HDSL Loop 2 dropped below the user Margin Alarm Threshold (1 to 15). Setting the threshold to 0 (zero)
inhibits the alarm.
ACO Alarm Cut Off AM Alarm cut-off is in effect.
LAIS Local Alarm
Indicating Signal Indicates an AIS (all 1’s) pattern is being transmitted from the local G.703 output port.
RAIS Remote Alarm Indicating
Signal Indicates an AIS (all 1’s) pattern is being transmitted from the remote G.703 output port.
LOOPBACKS
NREM Network Remote Loopback Loopback at ERU-412 (remote) towards network initiated from
ERU-412 front panel pushbutton, or maintenance terminal, or by
pressing both the MODE and SEL pushbuttons on the ELU-319
front panel. See Figure 5.
NLOC Network Local Loopback Loopback at ELU-319 (local) towards network by pressing both the
MODE and SEL pushbuttons on the ELU-319 front panel. See
Figure 5.
CLOC Customer Local Loopback Loopback at ERU-412 (local) towards customer interface (CI)
initiated from the maintenance terminal or by pressing both the
MODE and SEL pushbuttons on the ELU-319 front panel. See
Figure 5.
CHREV Channels Reversed Channel (loop) 1 and 2 HDSL pairs are reversed at the ERU-412
line input ports.
CREM Customer Remote
Loopback Loopback at ELU-319 towards customer interface (CI) initiated from the maintenance terminal or by pressing both MODE and SEL
pushbuttons on the ELU-319 front panel. See Figure 5.

Section 150-319-254
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TABLE 6. GLOSSARY OF HIGAIN TERMS
Term Definition
MARGINS Indicates the excess signal to noise ratio, at either the ELU-319 or ERU-412, relative
to a 10-7 Bit Error Rate. 1st value is current margin, 2nd value is minimum margin
since (C)leared last, 3rd value is maximum value since cleared, and NA means Not
Available (loops are not synchronized). The normal range of a typical margin is from
6 to 22 dB.
PULSE ATTENUATION Indicates the attenuation of the 2B1Q pulse from the distant end. HiGain operates
with pulse attenuations in excess of 30 dB. This value is related to the cable pair’s
loss at 260 kHz. The pulse attenuation is a more direct indication of the loop
attenuation to the 2B1Q signal than the 260 kHz loss. The normal range of pulse
attenuation is from 1 to 32 dB.
PPM Indicates the relative offset (in parts per million) of the crystal oscillator in the ERU-
412 from the ELU-319’s crystal oscillator. Any value between -64 and +64 is
adequate. Values outside this range indicate out-of- tolerance components or
excessive temperature drift of critical components.
HDSL 24 Hour ES
(Errored Seconds) The number of 1-second intervals that contained at least 1 CRC error. This value is a running total of the last 24 hours.
HDSL 24 Hour UAS
(Unavailable Seconds) The number of seconds the HDSL loop was out of synchronization.
G.703 BPV Seconds
(ES) The number of seconds during which at least 1 bipolar violation was detected at the G.703 input.
G.703 UAS Count The number of seconds during which the G.703 input signal was absent (125 or
more consecutive zeroes).
ELU/Ver x.x-yyyy
ERU/ver x.x-yyyy “x.x” = the software version number of the ELU-319 or ERU-412.
“yyyy” = the list number of the ELU-319 or ERU-412.
5. SYSTEM MAINTENANCE MENU SCREENS
5.01 Figure 6 is the Maintenance Terminal MAIN
MENU Screen. Its eight sub-menus provide
many useful provisioning, test and monitoring tools.
Figure 7 shows the ELU-319 SPAN STATUS
Screen.
5.02 Figure 8 shows the SET CLOCK menu.
Both the Time and Date are set with this
menu. Set the hours and minutes, using the military
(24-hour) convention. Setting the seconds is
optional. Enter the date in the sequence and format
shown. The ERU-412 unit can also be set to the
same time and date as the ELU-319 by entering a U
to the “Update Remote” query. All time information
is lost when power is removed. The last date,
however, is retained in NVRAM and reappears when
power is restored.
5.03 Figure 9 shows the SYSTEM SETTINGS
Screen. All 5 user options can be set from
this screen. To change any option, enter its
character key which is shown inside the parenthesis
within each parameter description. This causes the
screen to refresh with the new parameter. After all
parameters have been selected, press E(Exit) then
C(Confirm). The newly selected parameters are
now activated.
5.04 Figure 10 shows the LOOPBACK MENU
Screen for non-Doubler applications.
Loopbacks NLOC, NREM, CLOC and CREM are
available.

Section 150-319-254
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5.05 Figure 11 shows the PERFORMANCE
DATA screen for non-Doubler applications.
Both the Errored and Unavailable Seconds for both
HDSL loops and each G.703 input are listed at 15-
minute intervals over a four hour time interval.
Earlier and later data, in four-hour chunks on six
different screens, can be accessed by pressing P
(Previous) or N (Next) respectively. All of the
counters can be set to zero by pressing C (Clear)
from the ELU-319 SPAN STATUS Screen shown in
Figure 7. Note that since the ELU is considered the
master module, this clears
all performance data
screens at both the ELU-319 and the ERU-412. The
RS-232 terminal interface at the ERU-412 does not
allow the counters to be cleared.
5.06. Figure 12 shows the 7-DAY
PERFORMANCE HISTORY Screen. The
“Errored Seconds” and “Unavailable Seconds” for
both HDSL loops and each of the two G.703 inputs
are listed for the current and previous seven days.
All of the counters can be set to zero by pressing C
(Clear) on the SPAN STATUS Screen (Figure 7).
Note that since the ELU is considered the master
module, this clears
all performance data screens at
both the ELU and the ERU. The RS-232 terminal
interface at the ERU-412 does not allow the
counters to be cleared.
5.07 Figure 13 shows the ALARM HISTORY
Screen for non-Doubler applications. The
alarms are defined in Section A Paragraph 4.02.
The “First” and “Last” columns contain the time and
date stA of the first and last occurrence of each
alarm. The “Current” column shows the status of
each alarm. The “Count” column lists the number of
times each alarm occurred. All the data can be
cleared by pressing C(Clear). The maximum non-
overflowing count is 999.
5.08 Selection “H” from the main menu allows the
Circuit ID # to be set. It is limited to 24
alpha- numeric characters. It, like the system
settings, is stored in NVRAM and thus remains
when power is lost. Note that the Circuit ID # is not
available at the ERU-412 Maintenance Port.

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Figure 6. Main Menu.
Figure 7. Span Status Display (no Doubler).

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Figure 8. Set Clock Menu.
Figure 9. System Settings Menu.