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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.
100
LP1 Tip
101
LP1 Ring
102
103
104
LP2 Tip
105
LP2 Ring
106
Test Rx
107
Test Tx
108
DSX-1 Rx Tip
109
DSX-1 Rx Ring
110
111
112
113
DSX-1 Tx Tip
114
DSX-1 Tx Ring
115
116
Alarm (to Alarm Module)
117
-48V Return
118
Frame Ground
119
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
-48V
217
218
219
HDSL Loops 1 and 2 are full duplex
loops -- capable of simultaneously
transmitting and receiving data.
Figure 3. HTU-C Edge Connector Wiring
6
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).
2B1Q
HDSL
Figure 4. HTU-C Span Powering Diagram
Alarm Connections
The following alarm signal is connected to the
DDM Plus Alarm Module:
Pin
Label
117 ... LOS and Fuse Alarm ... Loss of signal and fuse
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.
Section 61245003L6-5, Issue 5
LOOP 1
SPAN POWER
SPAN CURRENT
REGULATOR
LOOP 2
Function
alarm of -48 V supply
T (26)
R (27)
T1 (34)
R1 (35)
61245003L6-5E
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