High Speed Transmission Equipment
Central Office Site
Remote Site
HDSL transceiver unit
HDSL transceiver unit
DS-1 Rate
DS-1 Rate
Interface
(1.544 Mbps)
Interface
(1.544 Mbps)
784 kbps Full-Duplex loop
HTU-C
HTU-R
784 kbps Full-Duplex loop
< 12,000 ft, 200 kHz BW
+2.5 V signal level
2B1Q, ZO=135 W
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.
HTU-C/HTU-R Interface Protection
F1250T
Tip
P2300SC MC
P0080SA MC
TX
P2300SC MC
Ring
F1250T
Power
Sink
HDSL
Transceiver
F1250T
F1250T
Tip
P2300SC MC
P2300SC MC
P0080SA MC
RX
Ring
Figure 3.10 HDSL Protection
© 2002 Teccor Electronics
3 - 9
http://www.teccor.com
+1 972-580-7777
®
SIDACtor Data Book and Design Guide
TECCOR [ TECCOR ELECTRONICS ]
