LOOPBACK TESTING
Initiate loopback testing from the HiGain maintenance menus or use the MODE and SEL
buttons. The inband codes shown below can be sent by a test set.
List number (HLU version number)
RS-232 Craft port
Bantam 210 jack provides bidirectional communication
between the unit and an external terminal to allow
configuration and performance monitoring through the
maintenance terminal menus. (Use adapter,
part number 120-1035-01, for jack.)
CLEI code label
M
A
R
G
I
N
(dB)
HLU-388
HiGain HD
L
RS
232
STATUS
SETUP
MODE SEL
106
105
104
103
102
101
100
DSX-1RCV
DSX-1XMT
HDSL2
HDSL1
205
204
203
202
201
200
119
118
117
116
115
114
113
112
111
110
Ground Ground
Frameground
Fusealarm*
Ring1
Ring1
Tip1
Tip1
(Mgmt.bus)
Ring
Ring
Tip
Tip
(Factoryburn-in)
-48Vdc
219
218
217
216
215
214
213
212
211
210
209
208
207
206
109
108
107
* Fuse alarm is normally floating (0 to 80 Vdc maximum)
and at -48 Vdc (10 mA maximum) when activated.
Four-character display
Displays status, provisioning, and
alarm messages. See tables below
for a list of message descriptions.
Status LED
Reports the following conditions:
Self Test is in process or
a CREM or NLOC loop-
back is in effect
Green LED Normal operation
Flashing Green LED HDSL acquisition
Red LED Fuse alarm
Flashing Red LED System alarm
Yellow LED
FlashingYellow LED
Configuration number
System is in ARM mode
System option buttons (for manual setting of
system parameters)
Use MODE and SEL to manually modify user options,
initiate loopbacks, and display DSX-1 line parameters.
1
2
3
4
Press the MODE button for 2 seconds and release.
The front panel alternately displays the first
system parameter and its current setting.
Press SEL to step through all possible system
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 YES
message, or press MODE to cancel all changes.
5D
Table 1. A5LB Special Loopback Commands
Loopback Inband Code Description
ARM 11000. . . NI LPBK (2-in-5 arming code)
DISARM 11100. . . IR LPDN (3-5 disarming code)
NLOC and CREM D3D3 IOR LPBK (231 ± 2)
NDU1 and CDU1 C741 ILR-1 LPBK (10 bit errors)
NDU2 and CDU2 C754 LR-20 LPBK (200 bit errors)
NDU3 and CDU3 C743 ILR-3 LPBK (30 bit errors)
NDU4 and CDU4 C744 ILR-4 LPBK (40 bit errors)
NREM and CLOC C742 ILR-2 LPBK (20 bit errors)
For more detailed information about the Maintenance Terminal
screens, provisioning, and loopback mode testing, refer to the
HLU-388 List 5D technical practice, document number
150-388-154-xx. It can be downloaded from the Customer Site portion
of the ADC Web page at www.adc.com. To order a hard copy, please
contact your sales representative.
Table 2. Front-Panel Alarm Messages(a)
(a) Alarm (ALRM) displays prior to an alarm message. Pressing the SEL button initiates an Alarm Cutoff (ACO)
message.
Message Description
LOSW Indicates that one of the HDSL loops has lost sync.
LLOS Indicates that no signal is detected at the DSX-1 input to the HLU.
RLOS Indicates that 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 Loop 2 has dropped below the threshold set by the user.
NONE No alarm present.
Table 3. System Configuration Codes(a)
(a) To view system configuration codes, press the MODE button for 3 or more seconds.
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 Alternate Mark Inversion (AMI) or Bipolar with
8-Zero Substitution (B8ZS).
PLEV xxxx Indicates the HDSL line voltage in its LOW (-140 Vdc), HIGH (±112 Vdc), or DIS
(disabled) state.
Network Customer
Premises
HLU HDU1 HDU2 HRU
NLOC NDU1 NDU2 NREM
SMJK
TLOS
CREM CDU1 CDU4
CDU2 CLOC
HDU3 HDU4
NDU3 NDU4CDU3
D3D3 C741 C754 C743 C744 C742
A5LB Addressable Repeater Loopback Commands
Table 4. 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 (dB) 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.
FERR Framing bit error occurred at HLU DSX-1 input.
H1ES or H2ES HLU HDSL Loop 1 or Loop 2 CRC error.
nHDU Number (n) of doublers in the circuit.
INSL xxDB The maximum Insertion Loss (INSL) message appears followed by xxDB, where xx is
the maximum insertion in dB of all spans and loops.
LBPV A local bipolar violation has been received at the DSX-1 input to the HLU-388 List 5D.
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 numberof the span.
TLOS HRU is in a logic loopback state caused by a loss of its T1 input from the CI.
Table 5. System Settings
Display Code Description (default values in bold)
EQL Sets the equalizer to DSX-1 for: 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.
PWRF DIS = disables HDSL powering.
LOW = HDSL line voltage at -140 Vdc maximum.
AUTO = automatically switches between -140 Vdc for nondoubler applications and
±112 Vdc for doubler applications.
HIGH = ±112 Vdc for all applications.
BERT NONE = prevents generation of a system alarm due to excessive BER
1E-6 or1E-7 = alarm activateswhen BER threshold exceeds 10-6 or 10- 7, respectively.
LBTO Loopback timeout = NONE, 20, 60, 120 minutes.
LNCD Line code = places the HLU and HRU in B8ZS or AMI mode.
SAIS Enables (ENA) or disables (DIS) NREM/SMJK loopback mode.
MARG 0 to 15 dB; default is 4dB; can only be set through the Maintenance Terminal.
RDA Enables (ENA) or disables (DIS) remote DS1 LOS at HRU input.
ALMP Enables line to output an (AIS) payload of all ones or an (LOS) condition.
RTPV Enables (ENA) or disables (DIS) remote provisioning.
BPVT Enables (ENA) or disables (DIS) bipolar violation transparency (BVP).
CONF YES = confirms that all operating modes are to be updated to their current selections.
NO = prevents the most recently selected operating mode selection from being updated.
