HDSL4 239 H4R Repeater Installation and Maintenance Practice
2
61223445L2-5B
Description
The 239 H4R is designed for installation in pre-wired 239-sized outside plant (OSP) repeater
housings and apparatus cases. Up to three 239 H4R units work in conjunction with an
ADTRAN H4TU-C (HDSL4 Transceiver Unit for the Central Office) and an ADTRAN H4TU-R (T-
200 HDSL4 Transceiver Unit for the Remote End) to provide DS1 service on the local loop.
The H4TU-C unit receives DSX-1 input signals from the network through the chassis. It then
transports them across the HDSL4 circuit and terminates them through the H4TU-R unit,
which provides a traditional DS1 to customer equipment. The H4TU-C provides testing, provi-
sioning, and performance monitoring capabilities that address circuit status.
Features
The List 2 239 H4R has the same basic features as the List 1 239 H4R (P/N 61223445L1), and
enhanced features and capabilities.
Basic Features
The basic features of the 239 H4R include the following:
• TC PAM line coding
• Lightning protection
• In-band loopback control
• Standard 239 form factor repeater apparatus case design
• Bad Splice Detection (refer to
• Fast Retrain (refer to
• TSCAN
Enhanced Features
Enhancements include the following:
• Fault Bridging (refer to
• Ground Fault Segment Identification
• Loop-to-Loop Detection
• Isolation relays in the span-powering circuitry, between the network and customer sides of
the repeater.
• The ability to detect a ground fault or short on the customer side of the repeater.
Isolation Relays
Isolation relays are normally open without span powering. Once span powering is detected on
the network-side, the 239 H4R monitors the customer-side to determine if a short or ground
fault condition exists. If no short or ground fault is detected, the 239 H4R will close the relay,
allowing span powering to pass from the network to the customer side.