Section 150-231-134
Revision 01
Page 2
A. PRODUCT OVERVIEW
1. DESCRIPTION AND FEATURES
1.01
PairGain’s HiGain Line Unit Model HLU-231
Issue 1, List 3D (Figure 1) is the Central
Office (CO) side of a repeater-less T-1 transmission
system. When used in conjunction with an HRU-412
HiGain Remote Unit, the system provides 1.544
Mb/Sec transmission on two unconditioned copper
pairs over the full Carrier Serving Area (CSA) range.
The “D” designation in the list number indicates that
this line unit can be used in applications with or
without the HiGain Doubler unit (HDU-451).
The CSA includes loops up to 12000 feet of AWG 24
or 9000 feet of AWG 26 wire, including bridged taps.
The HiGain system uses HDSL (High-bit-rate Digital
Subscriber Line) transmission technology as
recommended by Bellcore TA-TSY-001210. HiGain
complies with TR-TSY-000063 (Network Equipment
Building System NEBS) Generic Equipment
requirements) and (TR-TSY-000499 (Transport
System Generic Requirements - TSGR) common
requirements.
1.02
Revision History of this practice.
Revision 01
February 10, 1995
a) Initial release.
b) The initial software release is v. 1.4.
1.03
HLU-231, List 3D features:
•
Selectable DSX-1 Pre-equalizer
•
V to -210 V self-adjusting line voltage for
HRU-412 and HDU-451 applications
•
Front Panel HDSL S/N Margin Display
•
Selectable Loopback activation codes
•
RS-232 maintenance port
•
Non-volatile front-panel operator setup
•
Front Panel DS1 splitting & bridging
access
•
Lightning and power cross protection on
HDSL interfaces
•
Kb/Sec full-duplex 2B1Q HDSL
Transmission on two pairs
•
Front panel status indicating LED
•
Automatic front-panel display blanking
•
DS1 LOS detector (125 consecutive zeros)
•
Margin threshold alarm
•
HAIS & SAIS options
•
Easy return to factory default user settings
•
New T-1 transceiver chip
•
Circuit ID option
2. APPLICATIONS
2.01
HiGain provides a cost-effective, easy to
deploy method for delivering T-1 High
Capacity Digital Service (HCDS) over metallic pairs.
The fiber-like quality service is deployed over two
unconditioned, non-loaded copper pairs. Conventional
in-line T-1 repeaters are not required. Cable pair
conditioning, pair separation and bridged tap removal,
are not required.
2.02
The general guidelines require that each loop
have less than 35 dB of loss at 196 KHz, with
135 Ohm driving and terminating impedances. The
HiGain system operates with any number of other T-1,
POTS, Digital Data Service (DDS) or other HiGain
Systems sharing the same cable binder group.
HiGain systems can be used with customers requiring
DS1 service on a temporary or permanent basis.
HiGain also provides a means of quickly deploying
service in advance of fiber-optic transmission
systems. With HiGain, service can be provided within
hours. Fiber optic systems can be installed at a
leisurely pace and cut-over from HiGain when
convenient to do so. The HiGain system can then be
easily removed and utilized elsewhere.
3. SPECIFICATIONS
HDSL Line Code
784 Kb/Sec 2B1Q
HDSL Output
+13.5 dBm ± 0.5 dB @ 135 Ohms
HDSL Line Impedance
135 Ohms
Maximum Provisioning Loss
35 dB at 196 KHz, 135 Ohms
Line Clock Rate
Internal Stratum 4 clock
HDSL Startup Time
30 seconds typical, 60 seconds max per span
One-way DS1 Delay
<220 microseconds per span
DSX-1 Line Impedance
100 Ohms
