150-231-185-05, Revision 05
Overview
HLU-231 List 8E
September 13, 1999
3
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 8E 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 8E 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.
Personal Communications System Applications
The HLU-231 List 8E is required for Personal Communications System (PCS) applications that use the
HRU-411. The HRU-411 has an onboard 130 Vdc, 8.5 W power supply that can power the 200 mW PCS remote
radio ports. The line unit recognizes the HRU-411 (if CPE POWER switch is set to ON) and performs the
following two functions required by the HRU-411 to bring up the NEC radio port:
•
Increases the HDSL line voltage to its high ±112 Vdc level with the PWRF option set to AUTO
•
Enables HRU-411 to turn on its 130 Vdc radio port supply
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 61
.
For additional information about associated HiGain equipment, refer to the respective HiGain
technical practice (see
“Appendix D - Product Support” on page 63
).
