ADTRAN DDM Plus HTU-C Instruction Manual

61245003L6-5E Section 61245003L6-5, Issue 5 1
Section 61245003L6-5E
Issue 5, April 2001
CLEI Code #T1L4S4TC_ _
1. GENERAL
The ADTRAN DDM Plus HDSL Transceiver Unit
for the Central Office (HTU-C) (ADTRAN P N
1245003L6) is the Central Office (CO) unit used to
deploy a repeaterless T1 circuit using 4-wire
metallic facilities. The unit occupies one slot in an
AT&T DDM Plus DS1 Extension shelf. The unit is
illustrated in Figure 1.
DSX-1 signals are provided to and from the network
while 2B1Q HDSL signals are provided to the local
loop. The ADTRAN HTU-C works in conjunction
with the ADTRAN HDSL Transceiver Unit for the
Remote end (HTU-R) and HDSL Range Extender
(HRE) to provide a DS1 service up to 36,000 feet on
the local loop.
This HTU-C works with multiple list versions of the
HTU-R and HRE as listed below:
• 1244021L1, Low Voltage HTU-R T400 CP
• 1244022L1, Low Voltage HTU-R SA
• 1244041LX, Low Voltage T400 HRE
• 1244042L1, Low Voltage 819A HRE
• 1244044L1, Low Voltage 439 HRE
• 1245021L1, Low Voltage HTU-R T200 CP
• 1245022L1, Low Voltage HTU-R SA
• 1245026L1, Low Voltage HTU-R CI
• 1245026L4, Low Voltage HTU-R
• 1245026L5, Low Voltage HTU-R w PRM
DDM Plus HTU-C
High-bit-rate Digital Subscriber Line
Transceiver Unit for the Central Office
Installation and Maintenance
Contents
1. GENERAL ......................................................................... 1
2. INSTALLATION............................................................... 4
3. CONNECTIONS................................................................ 6
4. HDSL SYSTEM TESTING............................................... 7
5. CONTROL PORT OPERATION...................................... 8
6. HDSL DEPLOYMENT GUIDELINES .......................... 17
7. TROUBLESHOOTING PROCEDURES ....................... 18
8. MAINTENANCE ............................................................ 18
9. PRODUCT SPECIFICATIONS ...................................... 18
10. WARRANTY AND CUSTOMER SERVICE ................ 18
Appendix A. HDSL Loopbacks........................................... A-1
Figures
Figure 1. ADTRAN DDM Plus HTU-C ............................. 1
Figure 2. DDM Plus HTU-C Option Switch Locations ..... 3
Figure 3. HTU-C Edge Connector Wiring ......................... 6
Figure 4. HTU-C Span Powering Diagram ........................ 6
Figure 5. HDSL Loopbacks ................................................ 7
Figure 6. RS-232 (DB9) Pin Assignments ......................... 8
Figure 7. Introductory Menu Screen ................................. 11
Figure 8. HDSL Main Menu Screen ................................. 11
Figure 9. Current System Status Screen ........................... 12
Figure 9A. Current System Status Screen -- HRE .............. 12
Figure 10. Performance History Screen.............................. 13
Figure 10A. Performance History Screen -- HRE................. 13
Figure 11. Loopback Options Screen ................................. 14
Figure 12. Self-Test Options Screen ................................... 14
Figure 13. Provisioning Screen ........................................... 15
Figure 14. Troubleshooting Display ................................... 15
Figure 15. Set Time Date Circuit ID .................................. 16
Figure 16. HDSL Deployment Guidelines ......................... 17
Tables
Table 1. UL CUL Telecommunications Codes .................... 3
Table 2. SW1 Rotary Switch Option Settings ...................... 4
Table 3. SW2 Option Settings .............................................. 4
Table 4. SW4 Option Settings .............................................. 4
Table 5. Power Consumption Worksheet ............................. 5
Table 6. Front Panel Indicator .............................................. 5
Table 7. Screen Abbreviations Defined................................ 8
Table 8. HDSL Loss Values ............................................... 17
Table 9. Loop Insertion Loss Data ..................................... 17
Table 10. Troubleshooting Guide ......................................... 18
Table 11. HDSL DDM Plus HTU-C Unit Specifications ... 19
Table A-1. HDSL Loopback Control Codes ........................ A-2
Table A-2. Inband Addressable Loopback Codes ................ A-3
Figure 1. ADTRAN DDM Plus HTU-C
HTU-C
1245003L6
R
S
2
3
2
S
T
A
T
U
S
1
2
3
O
N
0
1
2
3
4
5
6
7
Trademarks:Anybrandnamesandproductnamesincludedinthisdocumentare
trademarks,registered trademarks,ortradenames oftheirrespoective holders.

2 Section 61245003L6-5, Issue 5 61245003L6-5E
The HTU-C can be deployed in circuits consisting
of one HTU-C and one HTU-R. When deployment
requires the HRE, the HTU-C can be deployed with
one Low Voltage HRE (T400, 239, 439, or 819A)
and one Low Voltage HTU-R.
NOTE
When deployment requires the use of two HREs
the HTU-C can be deployed with two
T400 HREs (P/N 1244041L2) and one HTU-R
(P/N 1245021L1 or 1245026LX).
The HDSL local loop operates as two independent
subsystems each operating over a single twisted
pair. The HTU-C communicates over these two
twisted pairs to the HTU-R. Each subsystem carries
half of the total bandwidth along with a small
amount of overhead used for maintenance and
performance monitoring related functions.
System power and alarm bus connections are made
through the backplane of the DDM Plus shelf.
DSX-1 and HDSL signals are connected through the
wire-wrap pins related to each individual slot
located on the rear of the shelf.
The DDM Plus HTU-C uses a DC-to-DC converter
to derive its internal logic and span powering
voltages from the -48 Vdc office supply. The DDM
Plus HTU-C can span power HREs and HTU-Rs as
listed above. When used with HREs and HTU-Rs,
the HTU-C can be configured to span power the
Low Voltage HTU-R and Low Voltage HRE at
either less than -140 Vdc or -190 Vdc (for
applications requiring two HREs and an HTU-R).
Span powering voltages meet all requirements of
Class A2 voltages as specified by Bellcore
GR-1089-CORE.
The HTU-C contains onboard fuses. If a fuse
opens, it supplies a -48 Vdc voltage to the fuse
alarm bus and all front panel indicators will be off.
These fuses are not designed to be field replaceable.
The DDM Plus HTU-C uses a DC-to-DC converter
to derive its internal logic and span powering
voltages from the -48 Vdc office supply.
Revision History
This practice has been reissued to incorporate a
CLEI code change.
Electrical Code Compliance
Table 1 shows the UL CUL Telecommunications Codes
for the DDM Plus HTU-C. The DDM Plus HTU-C
complies with the requirements covered under UL
1459 third edition and is intended to be installed in an
enclosure with an Installation Code (IC) of “B” or “E.”
NOTE
• This product is intended for installation
in RESTRICTED ACCESS
LOCATIONS only.
• Input current at maximun load is 1 A at -
48 Vdc.
• Maximum output at overcurrent
condition is 160 mA at -188 Vdc.
2. INSTALLATION
After unpacking the unit, immediately inspect it for
possible shipping damage. If damage is discovered,
file a claim immediately with the carrier, then
contact ADTRAN Customer Service (see subsection
10 of this practice).
The DDM Plus HTU-C plugs directly into the
AT&T DDM Plus shelf. The unit may be plugged
into any of the 28 numbered slots in this shelf. No
installation wiring is required.
Code Input Output
Installation Code (IC) A –
Telecommunication Code (TC) – X
Power Code (PC) F C
Table 1. Telecommunications Codes
C A U T I O N
C A U T I O N
!
SUBJECT TO ELECTROSTATIC DAMAGE
OR DECREASE IN RELIABILITY.
HANDLING PRECAUTIONS REQUIRED.

61245003L6-5E Section 61245003L6-5, Issue 5 3
One eight-position rotary switch (SW1), one
three-position Dip switch pack (SW2), and one
three-position slide switch (SW4) are used to
configure the mode of operation. Figure 2 shows
the location of these switches.
Figure 2. DDM Plus HTU-C Option Switch Locations
T1
0
1
2
3
4
5
6
7
1
2
3
O
N
SW1 SW2
B8ZS
LB
TMOUT
DIS
FT1AMIEN
O
N
CDILBKAIS
SW4
LVHV
SW3
0
1
2
3
4
5
6
7
SW1 T1
1
2
3
O
N
SW2
B8ZS
LB
TMOUT
DIS
FT1AMIEN
O
N
CDILBKAIS
SW4
LVHVSW3
P4
UNFR/AUTO
P4
UNFR/AUTO

4 Section 61245003L6-5, Issue 5 61245003L6-5E
The functions of the switches are described in
Tables 2 3 and 4. Configuration may be
performed by manually selecting each option
switch, or alternatively, may be performed using the
RS-232 craft access port.
Table 4. SW4 Option Settings
Position Description
CDI 3............. Customer Disconnect Indication. Upon customer Loss of Signal
(DS1) at the terminating end of the HDSL circuit, the HTU-R returns
DS1 Idle Signal to the network.
LBK .............. Upon customer Loss of Signal (DS1) at the terminating end of the
HDSL circuit, a logical network loopback is initiated at the HTU-R.
AIS................ Upon customer Loss of Signal (DS1) at the terminating end of the
HDSL circuit, AIS is generated from the HTU-R toward the network.
Table 2. SW1 Rotary Switch Option Settings 1
(This rotary switch is used to select operation of the line build-out equalizer in series with the DSX-1 output.)
Position Label Description
0 .................... 0 .................... Line length from 0-133 feet of ABAM cable
1 .................... 133 ................ Line length from 133-266 feet of ABAM cable
2 .................... 266 ................ Line length from 266-399 feet of ABAM cable
3 .................... 399 ................ Line length from 399-533 feet of ABAM cable
4 .................... 533 ................ Line length from 533-655 feet of ABAM cable
5 ............................................ N A
6 ............................................ N A
7 ............................................ N A
1 The HTU-C transfers the local configuration to the HTU-R when circuit synchronization is achieved. The HTU-R then sets its
configuration to match the HTU-C.
Switch Label Description
SW2-1................................................... Latching Loopback
T1 ................................. Selects full T1 loopbacks
FT1 ............................... Enables DDS Latching Loopback operation
SW2-2................................................... Line Code Select
AMI .............................. Alternate Mark Inversion is selected
B8ZS` ........................... B8ZS line code is selected
SW2-3................................................... Loopback Timeout
EN ................................. Loopback Timeout is Enabled 2
LB TMOUT DIS ......... Loopback Timeout is disabled
Table 3. SW2 Option Settings 2
(Default settings are indicated in bold typeface)
2 120-minute timeout is the default for Loopback Timeout Enabled.
3 The CDI is generated by transmitting the framing received from the network while overwriting the payload with a repeating pattern.
For applications where the DS1 is Extended Superframe, the data link is overwritten with a Yellow Alarm that is interrupted once every
second by a 100 millisecond code burst of 7E HEX.

61245003L6-5E Section 61245003L6-5, Issue 5 5
Framing
One jumper (P4) is used to select between
Auto-framed and Unframed operation. With the
jumper strap applied, Auto-framed operation is
selected; with the jumper strap removed, Unframed
operation is selected.
Powering Options
Using SW3, illustrated in Figure 2, the HTU-C can
be optioned for two different span powering modes.
By selecting “LV” span powering mode, the HTU-C
will provide span powering at less than -140 Vdc.
This mode allows for span powering of circuits
without HREs or with one HRE.
By selecting “HV” span powering mode, the
HTU-C will provide span powering at -190 Vdc.
This mode allows span powering of circuits with
two HREs and an HTU-R.
Shelf Population (based on power
requirements)
Table 5 can be used to determine the maximum
allowable shelf population using the DDM plus
shelf.
Typically the AT&T DDM Plus shelf is fused at
10 amps per side (one half of the shelf).
Several HTU-Cs can be mixed with other DDM
Plus standard plug-ins, providing that the total
current draw per shelf side is less than or equal to
5A. Refer to the original equipment manufacturer's
specifications for more detail on specific power
requirements of these units.
Faceplate Indicator
The HTU-C has one faceplate LED which indicates
operational status. Table 6 defines this LED.
4 The DS1 Alarm will be activated if and only if sealing current has been present on the HDSL loops.
HTU-C
S
T
A
T
U
S
R
S
2
3
2
1245003L6
Indicator Description
STATUS ............... Blinking Red ........ Signal Quality of 0 or No Sync on at least one loop
Solid Red .............. Alarm on any of HTU-C loops, HRE loops, DSX, or DS1 4
Blinking Amber.... In-band loopbacks armed
Solid Amber ......... Loopbacks active
Blinking Green ..... ES, SES, or BPV occurred
Solid Green........... Everything functioning normally
Table 6. Front Panel LED Indicator
Table 5. Power Consumption Worksheet
Step 1 Enter size of fuse for shelf (Amps) ................................................................
(Size required for over current protection (i.e., 100%, 75%, 50%)...............
Step 2 Determine the mix of HDSL circuits in shelf.
Percentage of circuits with an HTU-R only ...................................................
Percentage of circuits with one HRE and an HTU-R ....................................
Percentage of circuits with two HREs and an HTU-R ..................................
Step 3 Determine the current draw of the HDSL circuits.
Multiply (C) by 0.2 Amps (with no HRE) .....................................................
Multiply (D) by 0.3 Amps (with one HRE) ...................................................
Multiply (E) by 0.51 Amps (with two HREs) ................................................
Step 4 Add (F) through (H) to get total current draw ...............................................
Step 5 Divide (B) by (I) to get the number of units per shelf ...................................
(A) _____ Amps
(B) _____ Amps
(C) _____ %
(D) _____ %
(E) _____ %
(F) _____ Amps unit
(G) _____ Amps unit
(H) _____ Amps unit
(I) _____ Amps unit
_____ Units shelf*
* If the number of units shelf is greater than or equal to the shelf’s slot availability, full
shelf population is allowable.

6 Section 61245003L6-5, Issue 5 61245003L6-5E
3. CONNECTIONS
The DDM Plus HTU-C occupies one card slot in an
AT&T DDM Plus shelf. Power and alarm signals
are provided to the card through the backplane of
the shelf. DSX-1 and HDSL loop signals are
connected to the shelf connector and transmitted to
the corresponding slot the unit occupies. See
Figure 3 for HTU-C edge connection wiring.
Figure 3. HTU-C Edge Connector Wiring
The HTU-C is capable of span powering the HTU-R
by applying simplex current to the local loop. From
30 to 155 mA of current is coupled onto the HDSL
span to power the HTU-R and HRE when deployed.
The span powering voltage can be configured to be
either less than -140 volts or -190 volts with Loop 1
providing the negative voltage and Loop 2 the return
(see Figure 4).
Alarm Connections
The following alarm signal is connected to the
DDM Plus Alarm Module:
Pin Label Function
117 ... LOS and Fuse Alarm ... Loss of signal and fuse
alarm of -48 V supply
Alarm processing is actually performed by the
DDM Plus Alarm Module. Refer to the DDM Plus
Alarm module documentation for further
information.
Alarm conditions are not reported at the DDM Plus
HTU-C until the HDSL circuit is terminated by
connecting an HTU-R. This allows circuit pack
pre-provisioning. Once the HTU-C is terminated
with an HTU-R, the unit will go into an in-service
state.
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
LP1 Tip
LP1 Ring
HDSL Loops 1 and 2 are full duplex
loops -- capable of simultaneously
transmitting and receiving data.
LP2 Tip
LP2 Ring
Test Rx
Test Tx
DSX-1 Rx Tip
DSX-1 Rx Ring
DSX-1 Tx Tip
DSX-1 Tx Ring
Alarm (to Alarm Module)
-48V Return
Frame Ground
-48V
Figure 4. HTU-C Span Powering Diagram
SPAN POWER
REGULATOR SPAN CURRENT
T (26)
R (27)
T1 (34)
R1 (35)
LOOP 1
LOOP 2
2B1Q
HDSL

61245003L6-5E Section 61245003L6-5, Issue 5 7
4. HDSL SYSTEM TESTING
The ADTRAN HDSL system provides extensive
ability to monitor the status and performance of the
DSX-1 signals, DS1 signals, and HDSL loop
signals. Detailed performance monitoring is
provided by the faceplate-mounted RS-232 Control
Port.
These features are valuable in troubleshooting and
isolating any system level problems that may occur
at installation or during operation of the HDSL
system.
HTU-C Loopbacks
The HTU-C responds to two different loopback
activation processes. First, loopback may be
commanded manually using the control port
interface. Figure 11 depicts the Loopback Options
Screen which provides for HTU-C, HTU-R and
HRE loopbacks.
Secondly, the HTU-C responds to the industry
defacto standard for HDSL loopbacks. A detailed
description of these loopback sequences is given in
Appendix A.
The loopback condition imposed in both cases is a
logic level loopback at the point within the HTU-C
where the DSX-1 signal passes into the HDSL
modulators. Figure 5 depicts all the loopback
locations possible with ADTRAN HDSL
equipment.
In addition to network-side loopbacks, the HTU-C
provides customer-side loopbacks initiated by using
the terminal control port. In this mode, an AIS
signal is supplied to the network.
Figure 5. HDSL Loopbacks
HTU-C M
LOCAL
LOOP
HTU-R Customer-Side Loopback
HTU-R
HTU-C M
LOCAL
LOOP
HTU-C Customer-Side Loopback
HTU-R
X
X
DSX-1
HTU-C M
LOCAL
LOOP
HTU-R Network-Side Loopback and/or
HTU-R NIU Loopback
HTU-RXDS1
DS1
DS1
X = Signal Inactive
D = Data Sent
DSX-1
HTU-C M
LOCAL
LOOP
HTU-C Network-Side Loopback
HTU-R
D * DS1
X
AIS
D
AIS
HTU-C M
Dual HRE Network-Side Loopback
HRE
DSX-1 HRE
HTU-C M
HRE Network-Side Loopback
HTU-R
DSX-1 HRE
HTU-R
X
XDS1
AIS
HTU-C M
LOCAL
LOOP
HTU-R Bilateral Loopback
HTU-R
DS1
* = This signal will be AIS if using 1245026Lx HTU-R.
X
XDS1
AIS

8 Section 61245003L6-5, Issue 5 61245003L6-5E
5. CONTROL PORT OPERATION
The HTU-C provides a faceplate-mounted DB-9
connector that supplies an RS-232 interface for
connection to a controlling terminal. The pinout of the
DB-9 is illustrated in Figure 6.
The terminal interface operates at data rates from
1.2 kbps to 19.2 kbps. The asynchronous data
format is fixed at 8 data bits, no parity, and 1 stop
bit. The supported terminal type is VT100 or
compatible.
NOTE
If you are using a personal computer (PC) with
terminal emulation capability be sure to disable
any power saving programs. Otherwise
communication between the PC and the HDSL
unit may be disrupted resulting in misplaced
characters or screen timeouts.
Operation
For abbreviations used in the screen diagrams, see
Table 7.
Figure 6. RS-232 (DB-9) Pin Assignments
6
7
8
9
1
2
3
4
5
TXD (Transmit Data)
RXD (Receive Data)
SGN (Signal Ground)
Table 7. Screen Abbreviations Defined
Abbreviation Definition
ES ......................... Errored Seconds
DSX DS1 ......... (SF) ....... Second in which a BPV or frame bit error occurs.
(ESF) .... Second in which a BPV or CRC error occurs.
HDSL ............................... Second in which a CRC error occurs.
SES ....................... Severely Errored Seconds
DSX DS1 ......... (SF) ....... Second in which 1544 BPVs or 8 frame bit errors occur.
(ESF) .... Second in which 1544 BPVs or 320 CRC errors occur.
HDSL ............................... Second in which 165 CRC errors occur.
UAS ...................... Unavailable Seconds
DSX DS1 ......................... Second in which there is a loss of signal or sync.
HDSL ............................... Second in which there is a loss of signal or sync.
SF.......................... Superframe Format
ESF ....................... Extended Superframe Format
B8ZS..................... Bipolar with 8 Zero Substitution
AMI ...................... Alternate Mark Inversion
LBO ...................... Line Build-Out
BPV ...................... Bipolar Violation
DSX DS1 ......................... Second in which a bipolar violation occurs.
NIU ....................... T1 Network Interface Unit
S N ........................ Serial Number
15M ...................... Fifteen-Minute period
24H ....................... Twenty-Four-Hour period

61245003L6-5E Section 61245003L6-5, Issue 5 9
The screens illustrated in Figures 7 through 15 are
for an HDSL circuit deployed with ADTRAN’s
Low Voltage HDSL technology. The circuit
includes an HTU-C, HTU-R, and HRE. This
scenario was chosen for inclusiveness of
functionality; however, other configurations are
possible and their displays will vary slightly from
those shown in this section.
Initiate a terminal session by entering multiple space
bar characters, which are used by the HTU-C to
determine the speed of the terminal. Then, the
Introductory Menu will appear, as illustrated in
Figure 7.
From the Introductory Menu, the Main Menu may
be selected. The Main Menu provides access to
detailed performance and configuration information,
as illustrated in Figure 8, HDSL Main Menu
Screen.
From the Main Menu, the following screens can be
accessed.
1. Current System Status
2. Performance History
3. ADTRAN Information
4. Loopback Options
5. Self-Test
6. Provisioning
7. Troubleshooting
8. Set Time Date Circuit ID
The Current System Status screen, illustrated in
Figure 9, provides quick access to status
information for both the HTU-C M R and the
HTU-R. Type “H” once to view the Current System
Status screen for the HRE #1; type “H” a second
time to view the Current System Status screen for
HRE #2. See Figure 9A for the HRE Current
System Status screen.
At each 15-minute interval, the performance
information is transferred to the 15-minute
performance data register accessed from the
Performance History screen. This unit supports the
display of performance information in 15-minute
increments for the last 24-hour period. At each
24-hour interval, the performance data is transferred
into the 24-hour performance data register also
accessed using the Performance History screen,
illustrated in Figure 10. Type “H” once to view the
Performance History screen for HRE #1; type “H” a
second time to view the HRE Performance History
screen for HRE #2.
Type the letter “Z” at the Current System Status
screen in order to reset the current performance
registers to zero on both the Current System Status
and Performance History screens.
LOSS ................. Pulse Attenuation Measurement 5
SYNC ................ HDSL Loop 1 and Loop 2 Sync
Status
ES 15M 24H ..... Errored Seconds 6
SES 15M 24H ... Severely Errored Seconds 6
UAS 15M 24H .. Unavailable Seconds 6
An indication of Pair Reversal (if present) appears at
the bottom of the first key column. Status and
configuration information for the DS1 and DSX-1
signals is located in the center of the screen near the
bottom.
5LOSS is typically several dB less than the insertion loss
measured at 200 kHz. The LOSS measurement is a better
indication of the loop’s attenuation of the 2B1Q signal than
the insertion loss measured at a single frequency. ADTRAN
HDSL can operate on cables with an excess of 30 dB LOSS.
6The first number is for the current 15-minute period and the
second is the current 24-hour period (Loop 1 and Loop 2
numbers are displayed).
FRAME ...... T1 Framing Format selected
CODE ......... T1 Line Code selected
LBO ............ Line Build-Out selected (for DSX-1);
Customer Signal of 0 or -15 dB (for DS1)
NIU ............. Network Interface Unit enabled?
BPV ............ Bipolar Violations detected
(DSX-1 and DS1)
ES ............... Errored Seconds (DSX-1 and DS1)
SES ............. Severely Errored Seconds
(DSX-1 and DS1)
UAS ............ Unavailable Seconds (DSX-1 and DS1)

10 Section 61245003L6-5, Issue 5 61245003L6-5E
Alarms ........ Lists current alarm condition status
A measure of signal quality for each HDSL loop is
displayed in graphic form on the bottom of the
screen. The measure is from 0 (poor signal quality)
to 9 (excellent signal quality). Guidelines for
interpreting the indicators are given below.
0 ......... Noise margin is ≤ 0 dB (≈ 10-7 BER)
1-8...... Margin measurement above 10-7 BER in dB
9 ......... Margin is ≥ 9 dB (excellent quality) above
10-7 BER
The HDSL Loopback and Self-Test Option screens
are illustrated in Figures 11 and 12. Loopbacks and
Self-Test may be evoked or terminated using these
screens. A status of current loopback conditions is
also provided.
The Provisioning screen, illustrated in Figure 13,
displays the existing provisioning parameters. These
parameters cannot be changed via software but are
represented on this screen to inform the craftsperson of
the provisioned parameters. Options that can be
changed via hardware settings are marked with an
asterisk (*).
The Troubleshooting Display, illustrated in Figure
14, graphically depicts an HDSL circuit. The unit
reviews red, yellow, and blue alarm conditions in
the circuit to automatically predict where a fault is
located. Once a fault location is suspected, the
corresponding portion of the circuit on the screen is
highlighted and a message describing the failure
will appear.
The Set Time Date Circuit ID menu screen,
illustrated in Figure 15, provides additional
provisioning options. The time parameters are to be
entered as military time (for example, 3:15 p.m.
should be entered as “15:15:00”). The Circuit ID
can be entered as a 25-character string of
alphanumeric characters.

61245003L6-5E Section 61245003L6-5, Issue 5 11
Figure 8. HDSL Main Menu Screen
Figure 7. Introductory Menu Screen
CIRCUIT ID: Circuit XXXXX 02/01/99 11:16:27
ADTRAN
901 Explorer Boulevard
Huntsville, Alabama 35806-2807
---------------------- For Information or Technical Support -------------------
Support Hours ( Normal 7am - 7pm CST, Emergency 7 days x 24 hours )
Phone: [phone] / 888.873.HDSL Fax: [phone] Internet: www.adtran.com
-------------------------------------------------------------------------------
HTU-C INFORMATION SIGNAL QUALITY HTU-R INFORMATION SIGNAL QUALITY
----------------- [X] 9 [X] ----------------- [X] 9 [X]
S/N : A1875 L[X] 8 L[X] S/N : L[X] 8 L[X]
CLEI: T1L1B264AA O[X] 7 O[X] CLEI: O[X] 7 O[X]
MANF: 07/98 O[X] 6 O[X] MANF: / O[X] 6 O[X]
P[X] 5 P[X] P[X] 5 P[X]
HRE #1 INFORMATION [X] 4 [X] [X] 4 [X]
------------------ 1[X] 3 2[X] 1[X] 3 2[X]
S/N : j810C2360 [X] 2 [X] [X] 2 [X]
CLEI: T1R5PPYDAA [X] 1 [X] [X] 1 [X]
MANF: 04/98 [X] 0 [X] [X] 0 [X]
AT HTU-C AT HTU-R
Press “M” to view Main Menu.
CIRCUIT ID: Circuit XXXXX 02/01/99 11:19:06
ADTRAN HDSL MAIN MENU
1) CURRENT SYSTEM STATUS
2) PERFORMANCE HISTORY
3) ADTRAN INFORMATION
4) LOOPBACK OPTIONS
5) SELF-TEST
6) PROVISIONING
7) TROUBLESHOOTING
8) SET TIME/DATE/CIRCUIT ID

12 Section 61245003L6-5, Issue 5 61245003L6-5E
Figure 9. Current System Status Screen
Figure 9A. Current System Status Screen - HRE
CIRCUIT ID: Circuit XXXXX 02/01/99 11:15:34
LOOP #1 <NETWORK> LOOP #2 CURRENT SYSTEM STATUS LOOP #1 <CUSTOMER>LOOP #2
-------- HRE #1 --------- -------- HRE #1 ---------
00 dB 00 dB <- LOSS -> 31 dB 30 dB
YES YES <- SYNC -> YES YES
000/00000 000/00000 <- ES 15M/24H -> 000/00000 000/00001
000/00000 000/00000 <- SES 15M/24H -> 000/00000 000/00000
000/00012 000/00012 <- UAS 15M/24H -> 000/00016 000/00012
LOOPBACK INACTIVE HRE CUST PAIRS REVERSED LOOPBACK INACTIVE
HRE#1 NET SIGNAL QUALITY N = NETWORK SIDE RECEIVER HRE#1 CUST SIGNAL QUALITY
[X] 9 [X] C = CUSTOMER SIDE RECEIVER [X] 9 [X]
L[X] 8 L[X] L[X] 8 L[X]
O[X] 7 O[X] ____ ____ ____ O[X] 7 O[X]
O[X] 6 O[X] |HTUC| LOOP1 |HRE1| LOOP1 |HTUR| O[X] 6 O[X]
P[X] 5 P[X] | |========N| |C========| | P[X] 5 P[X]
[X] 4 [X] | | | | | | [X] 4 [X]
1[X] 3 2[X] | |========N| |C========| | 1[X] 3 2[X]
[X] 2 [X] |____| LOOP2 |____| LOOP2 |____| [X] 2 [X]
[X] 1 [X] [X] 1 [X]
[X] 0 [X] [X] 0 [X]
Press “Z” to zero registers, “M” for Main Menu
“P” for previous view.
CIRCUIT ID: Circuit XXXXX 02/01/99 11:14:38
LOOP #1 <NETWORK> LOOP #2 CURRENT SYSTEM STATUS LOOP #1 <CUSTOMER>LOOP #2
-------- HTU-C ---------- -------- HTU-R ----------
02 dB 02 dB <-- LOSS --> 32 dB 32 dB
YES YES <-- SYNC --> YES YES
000/00000 000/00000 <-- ES 15M/24H --> 000/00000 000/00000
000/00000 000/00000 <-- SES 15M/24H --> 000/00000 000/00000
000/00012 000/00012 <-- UAS 15M/24H --> 000/00016 000/00016
LOOPBACKS INACTIVE LOOPBACKS INACTIVE
HTU-C SIGNAL QUALITY DSX-1 DS1 HTU-R SIGNAL QUALITY
[X] 9 [X] ------------------------------ [X] 9 [X]
L[X] 8 L[X] ESF <- FRAME -> ESF L[X] 8 L[X]
O[X] 7 O[X] B8ZS <- CODE -> B8ZS O[X] 7 O[X]
O[X] 6 O[X] 0-133 <- LBO -> 0 dB O[X] 6 O[X]
P[X] 5 P[X] N/A <- NIU -> YES P[X] 5 P[X]
[X] 4 [X] 00001 <- BPV -> 00001 [X] 4 [X]
1[X] 3 2[X] 00001 <- ES -> 00001 1[X] 3 2[X]
[X] 2 [X] 00000 <- SES -> 00001 [X] 2 [X]
[X] 1 [X] 00000 <- UAS -> 00000 [X] 1 [X]
[X] 0 [X] NONE <- ALARMS -> NONE [X] 0 [X]
SEALING CURRENT PRESENT
Press “Z” to zero registers, “M” for Main Menu
“H” for HDSL Range Extender #1 (HRE) View.

61245003L6-5E Section 61245003L6-5, Issue 5 13
Figure 10A. Performance History Screen - HRE
Figure 10. Performance History Screen
CIRCUIT ID: Circuit XXXXX 02/01/99 11:16:06
24 HOUR REGISTERS PERFORMANCE HISTORY 15 MINUTE REGISTERS
--ES-SES-- --ES-SES-----ES-SES--
00001 00000 <--CURRENT--> 000 000
01/31 ----- ----- <-- --> 11:15 000 000 07:15 --- ---
01/30 ----- ----- | | 11:00 001 000 07:00 --- ---
01/29 ----- ----- | | 10:45 --- --- 06:45 --- ---
01/28 ----- ----- | | 10:30 --- --- 06:30 --- ---
01/27 ----- ----- |PREVIOUS | 10:15 --- --- 06:15 --- ---
01/26 ----- ----- | | 10:00 --- --- 06:00 --- ---
01/25 ----- ----- <-- | 09:45 --- --- 05:45 --- ---
| 09:30 --- --- 05:30 --- ---
VIEW 1 : HTU-C DSX-1 | 09:15 --- --- 05:15 --- ---
| 09:00 --- --- 05:00 --- ---
1-->|H|<--3----|H|-----4-->|H|--> | 08:45 --- --- 04:45 --- ---
|T| |R| |T| | 08:30 --- --- 04:30 --- ---
|U| |E| |U| | 08:15 --- --- 04:15 --- ---
<--|C|<--5-----|1|-----6-->|R|<--2 | 08:00 --- --- 04:00 --- ---
| 07:45 --- --- 03:45 --- ---
Press view number to select view --> 07:30 --- --- 03:30 --- ---
Press “H” to view HRE #1 history
Press “B” to go back 8 hours
Press “M” to return to the Main Menu
CIRCUIT ID: Circuit XXXXX 02/01/99 11:25:00
PERFORMANCE HISTORY <VIEW 1 - HRE NETWORK LP1 RECEIVER>
24 HOUR REGISTERS 15 MINUTE REGISTERS
---ES---SES-- --ES-SES----------ES-SES-
00000 00000 <---CURRENT---> 000 000
-1: ----- ----- <-- --> -1: 000 000 -17: 000 000
-2: ----- ----- | | -2: 000 000 -18: 000 000
-3: ----- ----- | | -3: 000 000 -19: 000 000
-4: ----- ----- | | -4: 000 000 -20: 000 000
-5: ----- ----- |PREVIOUS | -5: 000 000 -21: 000 000
-6: ----- ----- | | -6: 000 000 -22: 000 000
-7: ----- ----- <-- | -7: 000 000 -23: 000 000
| -8: 000 000 -24: 000 000
VIEW LOCATION DIAGRAM | -9: 000 000 -25: 000 000
| -10: 000 000 -26: 000 000
-->|H|<-----1->|H|-2------>|H|--> | -11: 000 000 -27: 000 000
|T| |R| |T| | -12: 000 000 -28: 000 000
|U| |E| |U| | -13: 000 000 -29: 000 000
<--|C|<-----3->|1|-4------>|R|<-- | -14: 000 000 -30: 000 000
| -15: 000 000 -31: 000 000
Press view number to select view. --> -16: 000 000 -32: 000 000
Press “H” to view HRE #1 history. Press “B” to go back 8 hours.
Press “M” to return to the Main Menu.

14 Section 61245003L6-5, Issue 5 61245003L6-5E
Figure 12. Loopback Options Screen
Figure 11. Provisioning Screen
CIRCUIT ID: Circuit XXXXX 02/01/99 11:17:30
LOOPBACK OPTIONS
_____ _____ _____
|HTU-C| |HRE 1| |HTU-R|
| | LP1 | | LP1 | |
--->|-----|<============>|-----|<============>|-----|<---
| | | | | |
NET | | | | | | CUST
| | LP2 | | LP2 | |
<---|-----|<============>|-----|<============>|-----|--->
| | | | | |
|_____| |_____| |_____|
1) LOOPBACK TO NETWORK AT HTU-C = INACTIVE
2) LOOPBACK TO CUSTOMER AT HTU-C = INACTIVE
3) LOOPBACK TO NETWORK AT HTU-R = INACTIVE
4) LOOPBACK TO CUSTOMER AT HTU-R = INACTIVE
5) LOOPBACK TO NETWORK AT HRE-1 = INACTIVE
6) LOOPBACK TO CUSTOMER AT HRE-1 = INACTIVE
Press corresponding number to toggle loopback option.
Press “M” to return to the Main Menu
CIRCUIT ID: Circuit XXXXX 02/01/99 11:18:17
PROVISIONING
___________________________________________________
| |
| PROVISIONS SETTINGS |
| ------------------------------------------ |
| * DSX-1 LINE BUILDOUT = 0-133 FEET |
| DS1 OUTPUT LEVEL = 0 dB |
| * DSX-1/DS1 LINE CODE = B8ZS |
| DSX-1 FRAMING = ESF |
| DS1 FRAMING = ESF |
| * LOOPBACK TIMEOUT = NONE |
| * CUSTOMER LOSS RESPONSE = CDI |
| * LATCHING LOOPBACK MODE = T1 |
| |
|___________________________________________________|
Provisions marked with an asterisk (*) can be changed
using switches on the HTU-C. DSX-1 and DS1 framing are
set automatically based on the received T1 framing.
DS1 output level can be changed using a strap on the
circuit board of the HTU-R.
Press “M” to return to the Main Menu

61245003L6-5E Section 61245003L6-5, Issue 5 15
Figure 14. Troubleshooting Display
Figure 13. Self-Test Options Screen
CIRCUIT ID: Circuit XXXXX 02/01/99 11:18:38
TROUBLESHOOTING DISPLAY
_____ _____ _____
|HTU-C| |HRE 1| |HTU-R|
| | | | | |
| | | | | |
--->| |<=========>| |<=========>| |<---
| | | | | |
NET | | | | | | CUST
| | | | | |
<---| |<=========>| |<=========>| |--->
| | | | | |
| | | | | |
|_____| |_____| |_____|
NO ALARM CONDITIONS
Press “M” to return to the Main Menu
CIRCUIT ID: Circuit XXXXX 02/01/99 11:17:51
SELF-TEST
Press “S” to initiate HTU-C and HTU-R self-tests.
Press “M” to return to the Main Menu.

16 Section 61245003L6-5, Issue 5 61245003L6-5E
CIRCUIT ID: Circuit XXXXX 02/01/99 11:12:52
SET TIME/DATE/CIRCUIT ID
1) SET TIME
2) SET DATE
3) SET CIRCUIT ID
Choose an option by pressing the corresponding number.
Press “M” to return to Main Menu.
Figure 15. Set Time/Date/Circuit ID Screen

61245003L6-5E Section 61245003L6-5, Issue 5 17
6. HDSL DEPLOYMENT GUIDELINES
The ADTRAN HDSL system is designed to provide
DS1 based services over loops designed to comply
with carrier service area (CSA) guidelines. CSA
deployment guidelines are given below.
1. All loops are non-loaded only.
2. For loops with 26-AWG cable, the maximum loop
length including bridged tap lengths is 9 kft.
3. For loops with 24-AWG cable, the maximum loop
length including bridged tap lengths is 12 kft.
4. Any single bridged tap is limited to 2 kft.
5. Total bridged tap length is limited to 2.5 kft.
6. The total length of multi-gauge cable containing
26-AWG cable must not exceed the following:
12 - {(3*L26) (9 - LBTAP)} (in kft)
L26 = Total length of 26-AWG cable
excluding bridged taps (in kft)
LBTAP = Total length of all bridged taps (in kft)
This deployment criteria is summarized in the chart
shown in Figure 16.
Loop loss per Kft for other wire is summarized in
Table 8.
Recommended maximum local loop loss
information for PIC cable at 70°F, 135Ω, resistive
termination is provided in Table 9.
Figure 16. HDSL Deployment Guidelines
0
12
11
10
9
8
7
6
5
4
3
2
1
01234
WORKING LENGTH OF 26 GAUGE CABLE (KFT)
WORKING LENGTH OF 24 GAUGE (OR COARSER) CABLE (KFT)
56789
2.5
INVALID HDSL CABLE LENGTHS
2.0 1.5 1.0 0.5 0.0
TOTAL
BRIDGED
TAPLENGTH
(KFT)
VALID HDSL CABLE LENGTHS
Cable Cable Temperature
Gauge Type 68°90°120°
26 ............... PIC .............. 3.902 ..... 4.051 ..... 4.253
26 ............... Pulp ............. 4.030 ..... 4.179 ..... 4.381
24 ............... PIC .............. 2.863 ..... 2.957 ..... 3.083
24 ............... Pulp ............. 3.159 ..... 3.257 ..... 3.391
22 ............... PIC .............. 2.198 ..... 2.255 ..... 2.333
22 ............... Pulp............. 2.483 ..... 2.45 ....... 2.629
19 ............... PIC .............. 1.551 ..... 1.587 ..... 1.634
19 ............... Pulp ............. 1.817 ..... 1.856 ..... 1.909
Table 8. HDSL Loss Values
(200 kHz cable loss in dB/Kft at 135Ω)
Table 9. Loop Insertion Loss Data
Frequency Maximum Loss
(Hz) (dB)
3,000................. 12.0
10,000 ................. 15.0
50,000 ................. 25.5
100,000 ................. 30.0
150,000 ................. 32.75
200,000 ................. 35.25
An approximation for the maximum amount of
wideband noise on an HDSL local loop as measured
by a 50 kbps filter is ≤31 dBrn.
An approximation for the maximum level of
impulse noise as measured using a 50 kbps filter on
an HDSL loop is ≤50 dBrn.
NOTE
These approximations are to be used as
guidelines only and may vary slightly on
different loops. Adhering to the guidelines
should produce performance in excess of
10-7 BER.

18 Section 61245003L6-5, Issue 5 61245003L6-5E
Condition:
Front panel indicator is off.
Solution:
1. Verify that -48 Vdc power is properly connected to the
shelf.
2. Inspect the fuse (F1) and verify that it is not blown.
3. Insert the HTU-C into a known good slot and check for
on condition of the STATUS indicator.
4. If Steps 1 and 2 pass, but Step 3 fails, replace the
HTU-C.
Table 10. Troubleshooting Guide
7. TROUBLESHOOTING PROCEDURES
Table 10 is a troubleshooting guide for the
ADTRAN DDM Plus HTU-C.
8. MAINTENANCE
The ADTRAN DDM Plus HTU-C requires no
routine maintenance. In case of equipment
malfunction, use the faceplate-mounted DB-9
RS-232 terminal interface to help in troubleshooting
the source of the problem.
ADTRAN does not recommend that repairs be
performed in the field. Repair services may be
obtained by returning the defective unit to the
ADTRAN Customer and Product Support (CAPS)
Department.
9. PRODUCT SPECIFICATIONS
Product specifications are detailed in Table 11.
10. WARRANTY AND CUSTOMER SERVICE
ADTRAN will replace or repair this product within
10 years from the date of shipment if it does not
meet its published specifications or fails while in
service (see ADTRAN Carrier Networks Equipment
Warranty, Repair, and Return Policy and
Procedure, document 60000087-10).
Contact Customer and Product Service (CAPS)
prior to returning equipment to ADTRAN.
For service, CAPS requests, or further information,
contact one of the following numbers
ADTRAN Sales
Pricing Availability
[phone]
ADTRAN Technical Support
Presales Applications Post-sale Technical Assis-
tance
[phone]
Standard hours: Monday-Friday, 7 a.m. - 7 p.m.
CST
Emergency hours: 7 days week, 24 hours day
ADTRAN Repair/CAPS
Return for Repair Upgrade
[phone]
Repair and Return Address
ADTRAN, Inc.
CAPS Department
901 Explorer Boulevard
Huntsville, Alabama 35806-2807

61245003L6-5E Section 61245003L6-5, Issue 5 19
Table 11. HDSL DDM Plus HTU-C Unit Specifications
(Part Number 1245003L6)
Loop Interface
Modulation Type .................................. 2B1Q
Mode ..................................................... Full Duplex, Echo Cancelling
Number of Pairs ................................... Two
Bit Rate ................................................. 784 kbps per pair
Baud Rate ............................................. 392K baud per pair
Service Range ...................................... Defined by Carrier Service Area Guidelines
Loop Loss ............................................. 36 dB maximum @ 200 kHz
Bridged Taps ........................................ Single Taps < 2000 feet, Total Taps < 2500 feet
Performance ......................................... Compliant with Bellcore TA-NWT-001210
HDSL Tx Signal Level ........................ 13.5 dBm
Input Impedance ................................... 135 Ω
Return Loss .......................................... 20 dB (40 kHz to 200 kHz)
Network Interface
4-WIRE DSX-1
DSX-1 Output Level ............................ 0 dB
DSX-1 Line Build Out ......................... 0-133 feet ABAM
134-266 feet ABAM
267-399 feet ABAM
400-533 feet ABAM
534-655 feet ABAM
DSX-1 Line Code ................................ AMI, B8ZS
DSX-1 Format ...................................... SF, ESF, Unframed
DSX-1 Channelization ......................... Channels 1-12 on Loop 1, Channels 13-24 on Loop 2
Power
Tested with the ADTRAN ow-Voltage HRE (P/N 1244041 2) and the ADTRAN ow-Voltage HTU-R (P/N 1245021 1)
Total Power .......................................... -48 Vdc @ 200 mA with HTU-R
-48 Vdc @ 300 mA with HTU-R and HRE
-48 Vdc @ 510 mA with HTU-R and two HREs
HTU-C M R Power Dissipation .......... 5.2 watts with HTU-R
6.2 watts with HRE and HTU-R
8.6 watts with two HREs and HTU-R
Span Power........................................... -137 or -190 Vdc nominal for voltage and current limit at 125 mA + -5%
(internally generated)
Fusing ................................................... 1.00 A (not field-replaceable)
Clock
Clock Sources ...................................... Internal, DSX-1 Derived
Internal Clock Accuracy ...................... ± 25 ppm, (exceeds Stratum 4). Meets T1.101 timing requirements.
Tests
Diagnostics ........................................... Self-Test, Local Loopback (HTU-C), Remote Loopback (HTU-R)
Physical
23" DDM Plus Shelf-Mounted
Dimensions ........................................... 3.51" High, .71" Wide, 9.89" Deep
Weight .................................................. Less than 1 lb.
Environment
Temperature ......................................... Operating (Standard): -40°C to +70°C; Storage: -40°C to +85°C
Control Port
Interface................................................ RS-232 (DB-9)
Terminal Type ...................................... VT100 or compatible
Async Speed ......................................... 2.4 kbps to 19.2 kbps
Data Format .......................................... 8 data bits, no parity, 1 stop bit

20 Section 61245003L6-5, Issue 5 61245003L6-5E