Appendix B - Functional Operation; Timing; Ground Fault Detect - ADC H4TU-C-388-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-319 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-388 List 1 is shown in
DSX-1 data 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), including D4, or Extended SuperFrame (ESF)
framing. When the data is unframed, the H4TU-C arbitrarily defines a frame bit.
Ring
110
DSX-1 IN
109
Tip
Frame ground
Tip1
114
DSX-1 OUT
115
Ring1
Factory use only 104
A
Fuse alarm
117
-48Vdc
217
Power supply
B
Ground
218, 118
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
T1
119 framer
Pre-
equalizer
select
Microprocessor
MODE SEL
Figure 34. H4TU-C-388 List 1 Block Diagram
D
ETECT
September 12, 2003
O
PERATION
Figure 34. The H4TU-C-388 List 1 receives a 1.544 Mbps
HDSL 1
XCVR
MUX
DEMUX
HDSL 2
XCVR
A
B
-185V or
± 123V HDSL
line voltage
power supply
(ground isolated)
STATUS
RS-232
(front panel)
LTPH-UM-1122-02, Issue 2
Tip
101
HDSL 1
102
Ring
Tip1
105
HDSL 2
106
Ring1
-
+
H4TU-C-388 List 1