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Appendix B - Functional Operation 152-388-100-02, Issue 2
52 June 6, 2000 H2TU-C-388 List 1
APPENDIX B - FUNCTIONAL OPERATION
ADC HDSL2 technology provides full-duplex services at standard DS1 rates over copper wires between an
H2TU-C and an H2TU-R, which comprise one HiGain system. HiGain systems use ADC Overlapped PAM
Transmission with Interlocking Spectra (OPTIS) transceiver systems to establish full-duplex, 1.552 kbps data
channels between the H2TU-C-388 List 1 and a remotely located H2TU-R.
Figure 30 shows a block diagram of the H2TU-C-388 List 1. The H2TU-C-388 List 1 receives a 1.544 Mbps
DSX-1 data stream from the DSX-1 digital cross connect interface. The H2TU-C-388 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 H2TU-C-388 recognizes Superframe (SF), including D4, or Extended Superframe (ESF)
framing.
Figure 30. H2TU-C-388 List 1 Block Diagram
TIMING
The low loop wander (0.5 UI max) of an H2TU-C-388, when used with a compatible remote unit, allows the
circuit to be used in all critical timing applications, including those that are used to transport Stratum 1 timing.
GROUND FAULT DETECT
The H2TU-C-388 has a Ground Fault Detect (GFD) circuit which detects a ground or a resistive path to ground
on any wire of the HDSL2 loop. This makes the product compliant with the Class A2 requirements of GR-1089.
HDSL1
XCVR
MICROPROCESSOR
A
B
109
115
110
114
119
104
FrameGND
ManagementBus
LEDs
Ring
Ring1
Tip
Tip1
-48Vdc
217
GND218,118
Fuse alarm 117
DSX-1IN
DSX-1 OUT
POWER
SUPPLY
B
A
PRE-
EQUALIZER
SELECT
T1
FRAMER
MODE
-185VdcHDSL
LineVoltage
PowerSupply
(GroundIsolated
andGroundFault
Detect)
SEL
RS-232
(front panel)
Tip1
+
_
101
102
Ring1
HDSL2
SPAN
HDSL2
Framer