Appendix B - Functional Operation; Timing; Ground Fault Detection - ADC HiGain H4TU-C-388 List 5A User Manual

LTPH-UM-1252-01
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 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 is shown in
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), including D4, or Extended SuperFrame (ESF) framing. When the data is
unframed, the H4TU-C arbitrarily defines a frame bit.
Tip
109
DSX-1 XMT
Ring 110
MON
LINE
Fuse alarm
117
-48Vdc
217
Power supply
B
Ground
218, 118
LINE
MON
Tip1 114
RCV
DSX-1
Ring1 115
Factory use only 104
Frame ground 119
T
IMING
The low loop wander (0.5 UI max) of an H4TU-C, when used with 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.
H4TU-C-388 List 5A
B - F
UNCTIONAL
Figure
A
T1
framer
Pre-equalizer
select
Microprocessor
STATUS
LEDs
Figure 34. H4TU-C Block Diagram
D
ETECTION
October 15, 2003
O
PERATION
34. The H4TU-C receives a 1.544 Mbps DSX-1 data stream
HDSL4
XCVR
Mux
Demux
HDSL4
XCVR
A
B
-185Vdc Power Supply
(Ground Isolated and

Ground Fault Detection)

RS-232

Appendix B - Functional Operation

Tip
101
HDSL4-L1
102
Ring
Tip1
105
HDSL4-L2
106
Ring1
-
+
H01174-A
57