Appendix B - Functional Operation; Timing; Ground Fault Detect - ADC H4TU-C-231-L1 User Manual

Appendix B - Functional Operation

A
PPENDIX
HDSL4 technology provides full-duplex services at standard T1 rates over two pairs of copper wire between an
H4TU-C, H4Ds (if necessary), and an H4TU-R which comprise one ADC system. ADC systems use Overlapped
Pulse Amplitude Modulation Transmission (OPAM) transceiver systems to establish two, full-duplex, 784 kbps
data channels between the H4TU-C-231 and a remotely located H4TU-R. This provides a total capacity of 1.568
Mbps between the two units.
A block diagram of the H4TU-C-231 is shown in
stream from the DSX-1 digital cross-connect interface. The H4TU-C contains a DS1 frame synchronizer
controlled by an 8-bit microprocessor that determines the type of framing on the DS1 stream and synchronizes to
it. The H4TU-C recognizes SuperFrame (SF) or Extended SuperFrame (ESF) framing. When the data is unframed,
the H4TU-C arbitrarily defines a frame bit.
Tip
42
D
XMT
S
43
Ring
X
1
BRG
SPAN
A
Fuse
32
Alarm
39
-48V
40
Power
B
Supply
15
GND
19
44
16
Network Management
46
Pre-equalizer
SPAN
D Select
S
X
BRG
1
Tip 1
49
RCV
50
Ring 1
T
IMING
The low-loop wander (0.5 UI max) of an H4TU-C, when used with compatible doublers and remote units, allows
the circuit to be used in all critical timing applications, including those that are used to transport Stratum 1 timing.
G F
ROUND AULT
The H4TU-C has a Ground Fault Detection (GFD) circuit which detects a ground or a resistive path to ground on
any wire of the HDSL4 loop. This makes the product compliant with the Class A2 requirements of GR-1089.
64
B - F
UNCTIONAL
Mux
T1
Framer
Demux
Mode Sel
Microprocessor
Status
Figure 34. H4TU-C-231 List 1 Block Diagram
D
ETECT
September 12, 2003
O
PERATION
Figure 34. The H4TU-C-231 receives a 1.544 Mbps DSX-1 data
A
-185V or ±123V HDSL Line
B
Voltage Power Supply
(Ground Isolated)
RS-232
LTPH-UM-1138-02, Issue 2
Tip 1
HDSL 1
HDSL 1
XCVR
Ring 1
Tip
HDSL 2
HDSL 2
XCVR
Ring
H4TU-C-231 List 1
34
35
26
27