Installation; Figure 2. Circuit Card Pin Assignments; Figure 3. Sw2 Option Labeling; Table A. Part Numbers - ADTRAN T400 DDST III Installation And Maintenance Manual

The DDST III can be optioned to pass the loop signal to
the CPE without regeneration. In this mode, regeneration
of an incoming signal will occur only in loopback, allowing
loops of up to 45 dB loss to be tested. For loops with
losses in excess of 34 dB, the regenerative mode of
operation can be selected to accommodate customer
equipment that requires a stronger signal to aid in lengthy
wiring extensions beyond the demarcation point. The
DDST III can receive signals that have been attenuated
by 45 dB from an OCU or OCU DP. The RPT/RPT OFF
option switch controls regeneration; in RPT mode the
DDST will output a -10dB signal to the customer's DSU/
CSU.
The DDST III is a single Type 400 mount circuit card
operating from -48 VDC supplied by the mounting
assembly. Table A provides applicable part numbers.
If the signal loss from the CO exceeds 34 dB, the unit
detects this condition and the >34 dB indicator on the
faceplate turns On .

Table A. Part Numbers

Description
T400 DDST III Circuit Pack
T400 DDST III Stand-alone
T400 Stand-alone Housing Only
When used in conjunction with ADTRAN high
performance OCUs or OCU DPs, the unit can be optioned
to provide extended range operation on loops with loss
to 45 dB 1 at all rates.

2. INSTALLATION

After unpacking the unit, immediately inspect it for possible
shipping damage. If damage is discovered, file a claim
immediately with the carrier, and then contact ADTRAN
Customer Service; see section 4, Warranty and
Customer Service .
• Never install telephone wiring
during a lightning storm.
• Never install telephone jacks in
wet locations unless the jack is
specifically designed for wet
locations.
• Never touch uninsulated telephone
wires of terminals unless the tele-
phone line has been disconnected
at the network interface.
• Use caution when installing or
modifying telephone lines.
1
Covered under ADTRAN patent number 4,759,035.
2
Wiring
The DDST III can be used in a standard T400 shelf or
housed in the ADTRAN T400 Stand-alone housing, part
number 1210007.
screwdown terminals of the barrier strip located in the
rear of the housing.
Wires should be connected as shown in Figure 2.
Connect the From Network pair to the terminals labeled
RR and RT. Connect the To Network pair to the terminals
labeled TT and TR. Connect the To Customer pair to the
terminals labeled DRT and DRR. Connect the From
Customer pair to the terminals labeled DTT and DTR.
Part Number
1212021L3
1212041L3
1210007
No rate selection is necessary for the DDST III. The unit
automatically adapts to the operating rate of the OCU in the
central office.
Optioning
The DDST III is equipped with one
Dual In-Line Package (DIP) switch
(SW2) that controls loopback
capability and regeneration.
See Figure 1, Figure 3, and Table
B for the location, labeling, and
description of the option settings.
The DDST III is sent from the factory with the option
switches set to LBK OFF and RPT OFF .
All option switches are located on the DDST III circuit card.
Function
Loopback
Enable
Repeat
Section 61212021L3-5, Issue 3
Connections are made using
T400
DDST III
-48 VDC
35 17
(TT)
41 55
To
Network
(TR)
47 49
(RT)
7 5
From
Network
(RR)
13 15

Figure 2. Circuit Card Pin Assignments

Table B. SW2 Option Settings

Switch/Description
SW2-1 (LBK)
On - Responds to CSU loopback
Off - Ignores CSU loopback
SW2-2(RPT)
On - Regenerates signals toward customer
Off - Passes signal to customer without
regeneration
Ground
(DTT)
From
Customer
(DTR)
(DRT)
To
Customer
(DRR)
OFF LBK
OFF RPT
Figure 3. SW2
Option Labeling
61212.021L3-5C