ADC H2TU-C-388 APPENDIX B - FUNCTIONAL OPERATION, TIMING, GROUND FAULT DETECT

Appendix B - Functional Operation 152-388-100-02, Issue 2

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.

Ring

DSX-1 IN		110
		109				HDSL 1
		Tip
						XCVR
			T1		HDSL2
					Framer
Frame GND		119	FRAMER
		Tip1
DSX-1 OUT		114	PRE-
			EQUALIZER
		115
			SELECT
		Ring1
					A
104	Management Bus				B	-185Vdc HDSL	+
			MICROPROCESSOR			LineVoltage
						Power Supply
		A				(Ground Isolated	_
Fuse alarm 117						and Ground Fault
						Detect)
-48Vdc		POWER	MODE SEL		RS-232
217				LEDs
B		SUPPLY			(front panel)

GND 218, 118

Tip 1

101

HDSL 2

SPAN

102

Ring 1

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.

52 June 6, 2000 H2TU-C-388 List 1