
LOOPBACK TESTING
Initiate loopback testing from the HiGain maintenance terminal screen or use the MODE
and SEL buttons. The inband codes below can also be sent by a test set.
Copies of this publication or the user manual can be downloaded from the ADC website at
www.adc.com. To order a hard copy, please contact your sales representative.
List 1 four-character display *
List 1 system option buttons (for manual
setting of system parameters) *
DSX-1 test access jacks
Card handle
List number
Status LED
Displays status, provisioning, and
alarm messages. See tables below
for a list of message descriptions.
Use MODE and SEL to manually modify user options,
initiate loopbacks, and display DSX-1 line parameters.
Connect standard test equipment.
List 1 craft port provisioning *
To access all system maintenance, provisioning
and performance screens, connect a standard
9-pin terminal cable between the serial port on a PC
and the H2TU-C craft port.
1
2
3
4
Press the MODE button for 1 second and release.
The front panel alternately displays the first
system parameter and its current setting.
Press SEL to step through all possible settings for
the displayed parameter.
Press MODE to update the parameter and advance
to the next parameter.
After scrolling through all the parameters, press SEL
to confirm changes when prompted with a CONF NO
message, or press MODE to cancel all changes.
LINE Provides splitting jack access to
(IN) and from (OUT) the HDSL2 span
at the DSX-1 interface.
BRG Provides non-intrusive bridging jack
access to (IN) and from (OUT) the
HDSL2 span at the DSX-1 interface.
Allows monitoring of the T1 payloads.
Maintenance Terminal Modem Settings
9600 baud
8 data bits
No parity
1 stop bit
Hardware flow control: OFF
Terminal emulation software: VT-100
S
E
L
M
O
D
E
HiGain
O
U
T
I
N
B
R
G
B
R
G
L
I
N
E
L
I
N
E
H
2
T
U
*
C
3
1
9
H
D
S
L
2
R
S
2
3
2
SETUP
STATUS
3
4
5
6
C
D
E
F
H7
8
J
9
K
10
L
GND
HDSL2SpanTip HDSL2SpanRing
System alarm Management bus
Frame ground -48V BAT
Fusealarm*
Factory use only
1
A
(IN)DSX-1Tip DSX-1Ring(IN)
2
B
(OUT)DSX-1 Tip1 DSX-1Ring1(OUT)
Card-edge connector
A Customer Remote (CREM)
loopback or a Network Local
(NLOC) loopback is in effect.
Green LED Normal operation.
HDSL2 acquisition or
system alarm.
Red LED Fuse alarm.
Flashing Red LED
Yellow LED
Flashing Yellow LED System is in Armed (ARM)
mode.
Off Line power is off.
(Configuration
number and
CLEI code
label on outside
of handle)
* Fuse alarm is normally floating
and at -48 Vdc when activated.
List 1C does not have a craft port, display,
or MOD and SEL buttons. To provision the List 1C,
access the maintenance terminal menus through
the management unit.
*
GNLB Loopback Commands
Loopback Inband Code Description
NLOC 1111000 DSX-1 signal is looped back to the network at the H2TU-C.
NREM 1110000 DSX-1 signal is looped back to the network at the H2TU-R.
SMJK 11000 DSX-1 signal is looped back to the network at the H2TU-R SmartJack
module.
CREM 1111110 Signal from customer is looped back to the customer at the H2TU-C.
CLOC 1111100 Signal from customer is looped back to the customer at the H2TU-R.
Loopdown 11100 Deactivates any of the above loopbacks.
Front-panel Alarm Messages
Message Description
System Alarm Messages (a)
(a) System alarm messages are listed in order of priority. ALRM displays prior to any alarm message. Pressing
the SEL button initiates an Alarm CutOff (ACO) message.
LOSW The HDSL2 loop has lost sync.
LLOS No signal is detected at the DSX-1 input to the H2TU-C.
RLOS No signal is detected at the DS1 input to the H2TU-R.
LAIS (b)
(b) Does not activate the alarm relay access pin H.
Local AIS Signal.
RAIS (b) Remote AIS Signal.
LRAI (b) An RAI condition is detected at the remote and the signal from the line unit is error-free.
RRAI (b) An RAI (yellow) alarm from the Customer Premises Equipment (CPE) with a failure
from the network.
DBER(b) A system DS1 Bit Error Rate (BER) alarm.
PRMF (b) H2TU-R Performance Report Messaging BER threshold exceeded at far end.
PRMN (b) H2TU-R Performance Report Messaging BER threshold exceeded at near end.
HBER A system HDSL2 Block Error Rate (BER) alarm.
MAL The margin on the HDSL2 loop has dropped below the threshold setting.
LA The attenuation on the HDSL2 loop has exceeded the maximum threshold value.
Line-power Alarm Messages (c)
(c) Line-power alarm messages display repeatedly as long as the alarm condition exists and are not included
in the priority order of the system alarm messages.
PWR FEED SHRT A short between the Tip and Ring of the HDSL2 pair.
PWR FEED GND The HDSL2 loop is grounded.
PWR FEED OPEN A line-power open condition.
Network Customer
Premises
H2TU-C H2TU-R
TLOS
NLOC CREM CLOC
1111000 110000
NREM
1110000 1111100
1111110
11000
SMJK
Front-panel Diagnostic Messages
Display Code Description (normal operating messages in bold)
A=xx The loop attenuation of the longest (maximum loss) span, measured in dB.
ACQ The multiplexers of the H2TU-C and H2TU-R are trying to establish synchronization.
AnL The multiplexers of the two devices on Span n are trying to establish synchronization with
each other, where nis the number of the span.
ARM Armed to respond to Intelligent Repeater Loop (ILR) codes.
BAD RT? The H2TU-C is not receiving a response from the H2TU-R.
FERR A framing bit error occurred at H2TU-C DSX-1 input.
FLDL Flash download of firmware updates. (Contact Customer Service for update procedures.)
HES H2TU-C HDSL2 loop cyclical redundancy check (CRC) error.
LBPV A local bipolar violation has been received at the DSX-1 input to the H2TU-C.
M=xx Indicates the power of the received HDSL2 signal relative to noise (S/N with respect to
21.5 dB). Any value of 6 dB or greater is adequate for reliable system operation.
MNGD The H2TU-C is under control of the HMU-319 network management unit.
PWR FEED OFF HDSL2 span power is turned off.
PWR FEED ON Indicates that the HDSL2 loop is not grounded or shorted.
SIG The transceivers of the H2TU-C and H2TU-R (or the H2TU-C and first regenerator) are
trying to establish contact with each other on Span 1 of the HDSL2 loop.
SnL The transceivers of the two devices on Span nare trying to establish contact with each
other, where nis the number of the span.
Front-panel Configuration Options Using MODE and SEL (List 1 Only) (a)
(a) Front-panel configuration options display in the order listed.
Display Code Description (default values in bold)
EQL Sets the DSX-1 Equalizer to: 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.).
RLBO Sets the H2TU-R line buildout to 0 dB, -7.5 dB, or -15 dB.
LPBK Enables (ENA) or disables (DIS) SmartJack loopback commands.
SPLB xxxx Configures the system for generic (GNLB) or special inband loopback commands (A1LB,
A2LB, A3LB, A4LB, A5LB).
PWRF OFF = disables HDSL2 powering. ON = HDSL2 line voltage is -185 Vdc maximum.
HBER 1E-6 or 1E-7 = alarm activates when the HDSL2 BER alarm threshold exceeds 10-6 or 10-7.
NONE = prevents generation of a system alarm due to BER.
DBER Enables (ENA) or disables (DIS) fixed 24-hour DSX-1 BER alarm threshold.
LBTO Loopback timeout = NONE, 20, 60, 120 minutes.
ALM Enables (ENA) or Disables (DIS) alarm indications on Pin H.
DS1 DSX-1 line code = AUTO, B8ZS, AMI.
FRMG DS1 frame formatting = AUTO (auto framing mode) or UNFR (unframed mode).
RDA Enables (ENA) or disables (DIS) alarm indications due to remote DS1 LOS at the H2TU-R
input.
ALMP Enables system to output an alarm pattern: AIS or LOS.
BPVT Enables (ENA) or disables (DIS) Bipolar Violation Transparency.
NLBP Enables the H2TU-R to transmit either AIS or LOS towards the CI for any network loopback.
TLOS Enables (ENA) or disables (DIS) a logic loopback at the H2TU-R when an LOS occurs at its
DS1 input.
RTPV Enables (ENA) or disables (DIS) remote provisioning.
Front-panel System Information Messages (Scroll Mode) (List 1 Only) (a)
(a) To scroll through system information messages, press the MODE button for 3 or more seconds.
Code Description Code Description
CODE xxxx Line code setting (AMI, B8ZS). LIST xx Product list number.
FRM xxxx Frame pattern received from the
DSX-1 (SF, ESF, UNFR). MARG xx Margin threshold (0 to 15 dB).
Default is 4.
LATT xx Loop attenuation threshold
(0 to 40 dB). Default is 35. VER x.xx Firmware version.
To comply with the intrabuilding wiring requirements of GR-1089
CORE, Section 4.5.9, the shields of the ABAM-type cables that
connect the H2TU-C DSX-1 output ports to the cross-connect panel
must be grounded at both ends.