6
Section 61246001L2-5, Issue 2
61246001L2-5B
Figure 3. HTU-C M Edge Connector Wiring
2B1Q
HDSL
SPAN POWER
REGULATOR
SPAN CURRENT
T (26)
R (27)
T1 (34)
R1 (35)
LOOP 1
LOOP 2
Figure 4. HTU-C M Span Powering Diagram
splitting jacks provide an intrusive, signal interrupting
access to the line. This permits parameters to be
measured such as loop resistance, background noise
level, insertion loss, etc. It is very important to know
the direction of the access provided by a metallic
splitting jack.
Figure 5 illustrates the complete Bantam jack
arrangement and details for specific jacks.
DSX-1
MON
RX
HTU-C
DATA
PUMP
LOOP DC
POWER SOURCE
DSX-1
T
R
DSX-1
T1
R1
HDSL
LOOP 1
HDSL
LOOP 2
HTU-C
HDSL
LOOP 1
HDSL
LOOP 2
EQ
RX
DSX-1
MON
TX
EQ
TX
Figure 5. HTU-C M Bantam Jack Arrangement
HTU-C M Loopbacks
The HTU-C M responds to two different loopback
activation processes. First, loopback may be activated
using the craft interface. The Loopback Options
Screen which provides for the HTU-C M, HTU-R, and
HRE loopbacks will be described in subsection 5.
Secondly, the HTU-C M 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 M
where the DSX-1 signal passes into the HDSL
modulators. Figure 6 depicts all of the loopback
locations possible with ADTRAN HDSL equipment.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
-48 RET
Loop 1 HDSL Tip (Wire-Wrap)
Chassis Ground
Loop 1 HDSL Ring (Wire-Wrap)
Loop 2 HDSL Ring (Wire-Wrap)
Loop 2 HDSL Tip (Wire-Wrap)
-48V(1)
DSX-1 Rx Tip (Wire-Wrap)
DSX-1 Rx Ring (Wire-Wrap)
-48 RET
DSX-1 Tx Tip (Wire-Wrap)
DSX-1 Tx Ring (Wire-Wrap)
Fuse Alarm
Input to HTU-C
Output from HTU-C
Input to HTU-C
Output from HTU-C
