L
OOPBACK
T
ESTING
Initiate loopback testing from the HiGain HDSL2 maintenance screen accessed through the
craft port. The inband codes can also be sent by a test set.
C
ONFIGURATION
The H2TU-C-202 List 4E has a configuration switch bank containing eight switches
(located on the printed circuit card). The switches are shown in the figure below and are
described in the Switch Descriptions table.
Copies of this publication or the H2TU-C-202 List 4E technical practice
(LTPH-TP-1099-xx) can be downloaded from the ADC website at www.adc.com. To order
a hard copy, please contact your sales representative.
Card handle
List number
Status LEDs
Report the following conditions:
DSX-1 test access jacks
Connect standard test equipment.
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.
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: VT100
CLEI code
label
ALM LED:
LOOP LED:
LBK LED:
-Solid red when a fuse alarm is present.
-Flashes red once per second while a
local alarm is present.
-Flashes red five times per second while a remote
alarm is present.
-Off when no alarm is present.
-Solid green while all HDSL2 spans are up.
-Flashes green once per second during
a loop acquisition on the span.
-Flashes green five times per second when a
margin or loop attenuation threshold is exceeded.
-Solid yellow when the system is in loopback, NLOC,
or CREM mode.
-Flashes yellow five times per second when the
system is armed.
-Off when the system is not armed and not in
loopback mode.
DSX LED:
-Solid green when DSX-1 signal is present and no
alarm is present.
-Flashes green once per second for BPV, FERR,
UAS, or CRC DSX-1 error.
-Flashes green five times per second when network
side framing or line code provisioning does
not match the DSX-1 signal being received.
-Off when the DSX-1 signal is not present.
Configuration Switch Bank (located on the board)
Card-Edge Connector
DSX-1 EQL Equalization
(switches 1-4)
AMI/B8ZS Line code
(switch 5)
LBTO Loopback timeout
(switch 6)
FT1 Fractional T1
(switch 7)
LCL/SPAN Local/Span Powering
(switch 8)
27
25
23
21
19
17
15
13
11
9
7
3
5
1
DS1 Ring1
DS1 Tip1
Management bus
Factory use only
HDSL2 Ring
Circuit ground
( - )
( + )
DS1 Ring
DSX-1 In
DS1 Tip
HDSL2 Tip
Chassis ground*
Fuse alarm
28
26
24
22
20
18
16
14
12
10
8
4
6
2
55
53
51
49
47
45
43
41
39
37
35
32
31
56
54
52
50
48
46
44
42
40
38
36
34
30
33
29
Note: Active pins are highlighted in black.
*Chassis ground may be tied to earth ground per local practice.
DSX-1 Out
HDSL2
Span
-48Vdc Local Power
Chassis ground*
Alarm
IN
l
BRG
l
OUT
H
2
T
U
*
C
2
0
2
H
D
S
L
2
RS-232
DCE
L
ALM
LOOP
LBK
DSX
D
S
X
1
4E
HiGain
HDSL2
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
DS1 signal from customer is looped back to the customer at the H2TU-C.
CLOC
1111100
DS1 signal from customer is looped back to the customer at the H2TU-R.
Loopdown
11100
Deactivates any of the above loopbacks.
Configuration Options Using Maintenance Terminal
Option Code Description (default values in bold)
EQL
Sets the DSX-1 Equalizer to: 0 (0 to 132 ft.), 133 (133 to 265 ft.), 266 (266 to 398 ft.), 399 (399
to 532 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.
FT1
Enables (ENA) or disables (DIS) system response to DDS latching loopback commands for
fractional T1 applications.
SPLB xxxx
Configures system for generic (GNLB) or special inband loopback commands (A2LB, A3LB, A4LB).
PWRF
OFF = disables HDSL2 powering; ON = HDSL2 line voltage is -180 Vdc.
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 pins 22 and 30.
MARG
Determines the minimum allowable margin below which a system alarm can occur: (5 dB) 0 dB to
-15 dB.
DS1
DSX-1 line code = B8ZS, AMI.
CONV
H2TU-R frame format conversion = OFF (framing determined by the DS1 FRMG option), ACON
(autodetection of framing and potential frame conversion at the H2TU-R), or FCON
(autodetection of framing and forced frame format conversion at the H2TU-R).
FRMG
DS1 frame formatting = AUTO (auto framing mode) or UNFR (unframed mode).
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 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.
LATT
Loop Attenuation Threshold (0 - 40 dB). Default = 32 dB.
RTPV
Enables (ENA) or disables (DIS) remote provisioning.
PRM
OFF = no enhanced Performance Report Messaging; SPRM = Supplemental PRM;
NPRM = Network PRM; S + N = SPRM + NPRM.
NAIS
If ALMP is set to AIS, NAIS option specifies which pattern is sent to the network when a remote
LOS or AIS occurs. CI = AIS-CI sent to the network; AIS = AIS sent to the network.
ROVR
Enables (ENA) or disables (DIS) conversion of an ESF DS1 payload from the network with an
embedded RAI pattern to an SF-RAI pattern towards the CI at the H2TU-R. CONV option must
be set to FCON or ACON.
RACI
Enables (ENA) or disables (DIS) conversion of a DS1 SF-RAI signal received by the H2TU-R to an
SF-RAI-CI signal towards the network.
PBON
Configures the power output levels of the H2TU-C network unit toward the customer to comply
with Default (DEF) or Enhanced (ENH) templates.
PBOC
Configures the power output levels of the H2TU-C customer unit toward the network to comply
with Default (DEF) or Enhanced (ENH) templates.
Network
Customer
Premises
H2TU-C
H2TU-R
TLOS*
NLOC
CREM
CLOC
1111000
NREM
1110000
1111100
1111110
11000
SMJK
When enabled, TLOS is an automatic loopback
that occurs with an LOS at the remote DS1 input.
*
DS1
DSX-1
The H2TU-C-202 List 4E does not have a display or MODE and
SEL pushbuttons. Set the switches on the on-board switch
bank or access the maintenance terminal screens through the
craft port to make configuration changes.
Switch Descriptions (default values in bold)
Leftmost Switch Position Options
Switch
Number
Rightmost Switch Position Options
Sets the equalizer to 133 to 265 feet
1
(a)
(a) Only one of the DSX-1 line equalization switches (1 - 4) can be selected at a time. If more than one switch
is enabled, the lowest value setting has priority.
0
Sets the equalizer to 266 to 398 feet
2
(a)
0
Sets the equalizer to 399 to 532 feet
3
(a)
0
Sets the equalizer to 533 to 655 feet
4
(a)
0
Selects the DSX-1 line code Alternate Mark
Inversion (AMI)
5
Selects Bipolar with 8-Zero Substitution
(B8ZS)
Enables the Loopback Timeout (LBTO) for
120 minutes
6
Disables LBTO
Enables Fractional T1 (FT1) loopback
capability
7
Disables FT1 loopback capability
Configures the system for Local powering
8
Configures the system for Span powering
