Appendix B - Functional Operation; Timing; Ground Fault Detection; Block Diagram - ADC HiGain H2TU-C-388 List 7F Manual

Appendix B - Functional Operation

A
PPENDIX
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 HDSL2 system. ADC systems use ADC Overlapped Pulse
Amplitude Modulation (OPAM) transceiver systems to establish a full-duplex, 1.552 kbps data channel between
an H2TU-C and a remotely located H2TU-R.
Figure 40 shows the H2TU-C block diagram. The H2TU-C receives a 1.544 Mbps DSX-1 data stream from the
DSX-1 digital cross-connect interface. The H2TU-C contains a DS1 frame synchronizer controlled by an 8-bit
microprocessor that determines the type of framing on the DS1 stream. The H2TU-C synchronizes to the type of
framing detected. The H2TU-C recognizes SuperFrame (
D
Tip
109
S
XMT
X
110
Ring
1
BRG
Fuse alarm 117
-48Vdc
217
B
GND 218, 118
Pre-equalizer
BRG
D
Tip 1
S
114
RCV
X
115
1
Ring 1
H0428-A
T
IMING
The low loop wander (0.5 UI max) of an H2TU-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 H2TU-C has a Ground Fault Detection (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.
66
B - F
UNCTIONAL
T1
A
Framer
POWER
SUPPLY
Select
Microprocessor
LEDs
Figure 40.
D
ETECTION
O
PERATION
SF ), including D4 or Extended SuperFrame (ESF).
HDSL2
Framer
A
-185 Vdc
B
(Ground isolated
and ground fault detect)
RS-232
Loopback pushbutton

Block Diagram

July 21, 2003
LTPH-UM-1214-02
HDSL 2
XCVR
+
Power
Supply
_
H2TU-C-388 List 7F
Tip
101
HDSL 2
SPAN
102
Ring