
High Speed Transmission Equipment
2002 Teccor Electronics
SIDACtor
Data Book and Design Guide
3 - 9
http://www.teccor.com
+1 972-580-7777
R
Figure 3.9
HDSL Overview
Protection Circuitry
Longitudinal protection is required at both the HDSL Transceiver Unit – Central Office
(HTU-C) and HDSL Transceiver Unit – Remote (HTU-R) interfaces because of the ground
connection used with loop powering. Two P2300SC MC
SIDACtor
devices provide
overvoltage protection and two F1250T
TeleLink
fuses (one on Tip, one on Ring) provide
overcurrent protection. (Figure 3.10) For the transceiver side of the coupling transformer,
additional overvoltage protection is provided by the P0080SA
SIDACtor
device. The
longitudinal protection on the primary coil of the transformer is an additional design
consideration for prevention of EMI coupling and ground loop issues.
Figure 3.10
HDSL Protection
DS-1 Rate
Interface
(1.544 Mbps)
DS-1 Rate
Interface
(1.544 Mbps)
Central Office Site
Remote Site
784 kbps Full-Duplex loop
784 kbps Full-Duplex loop
< 12,000 ft, 200 kHz BW
+2.5 V signal level
2B1Q, Z
O
=135 W
HTU-C
HTU-R
HDSL transceiver unit
HDSL transceiver unit
P2300SC MC
P2300SC MC
F1250T
F1250T
Tip
Ring
P0080SA MC
P2300SC MC
P2300SC MC
F1250T
F1250T
Tip
Ring
P0080SA MC
TX
RX
HDSL
Transceiver
Power
Sink
HTU-C/HTU-R Interface Protection