Overview
150-231-181-01, Revision 01
2
September 7, 1999
HLU-231 List 8A
•
Lightning and power cross protection on HDSL interfaces
•
Full duplex 2B1Q HDSL transmission on two pairs at 784 kbps
•
Margin threshold alarm
C
OMPATIBILITY
The HLU-231 List 8A is designed to be mounted in 220 mechanics shelves. For a list of compatible shelves, see
“Appendix C - Compatibility” on page 62
All generations of HiGain HLU and HRU modules are compatible with each other. To take advantage of the
enhanced features of newer HiGain doublers, refer to
“HiGain Doubler Circuit Deployment” on page 62
A
PPLICATIONS
HiGain systems provide a cost-effective, easy-to-deploy method for delivering T1 High Capacity Digital Service
(HCDS) over metallic pairs.
•
The service is deployed over two unconditioned, non-loaded copper pairs, yet it demonstrates a quality that
is competitive with fiber optics.
•
Conventional, in-line, T1 repeaters are not required.
•
Cable pair conditioning, pair separation and bridged tap removal are not required.
In general, HiGain systems:
•
Operate with any number of other T1, POTS, Digital Data Service (DDS) or other HiGain systems sharing
the same cable binder group
•
Can be used with customers requiring DS1 service on a temporary or permanent basis
•
Provide a means of quickly deploying service in advance of fiber-optic transmission systems.
With a HiGain system, service can be provided within hours. Fiber-optic systems can be installed incrementally
and cut-over from the installed HiGain system when convenient to do so.
HiGain Doubler Applications
For applications without doublers, the HLU-231 is directly connected to the HRU by the two HDSL cable pairs.
The HLU-231 List 8A is compatible with all HiGain HRUs.
For doubler applications, one to four doublers may be used in the HDSL loops between the HLU and HRU.
•
If the HRU is line-powered, the HLU-231 List 8A can power three doublers and the remote unit (HRU-402
or HRU-411) for a total of four spans.
•
If the HRU is locally powered, the HLU can power up to four doublers for a total of five spans.
These extended ranges are only available when using the HDU-409, HDU-404 or HDU-407
micro-doublers with the HRU-411 or HRU-402. Older doublers (HDU-451, HDU-439 and HDU-437)
cannot be used in circuits with more than two doublers in any line or local power system. For
compatibility guidelines on mixing newer doublers with older HRU and HLU models, refer to
“HiGain Doubler Circuit Deployment” on page 62
.
For additional information about associated HiGain equipment, refer to the respective HiGain
technical practice (see
“Appendix D - Product Support” on page 64
).
