Revision 02
January 12, 1998
Section 363-754-100-02
PG-Flex FRC-754 List 1
PairGain Engineering - Plant Series
Page 5
4.3
HDSL Transmission. PG-Flex utilizes HDSL transmission technology between the COT and RT
and provides up to 32 DS0s, plus signaling, over two copper pairs without the need for repeaters,
loop conditioning, or pair selection. Adaptive equalization, scrambling, and a four-level 2B1Q line
coding scheme increase range and minimize crosstalk.
4.4
The line interface is a two-pair, 1110-kbps full-duplex 2B1Q transmission format. The dual HDSL
lines provide thirty-two 64-kbps channels with signaling, and an embedded operations channel for
management control. The signal characteristics on the carrier pairs comply with TR-NWT-001210,
Generic Requirements for High-bit-rate Digital Subscriber Line (HDSL) Systems.
4.5
For the system configuration depicted in Figure 2, the maximum distance between the COT and the
RT is 10.7 kft (3.3 km), assuming the HDSL lines are 24 gauge (0.5 mm). Table 2 shows the
maximum distance between the COT and RT for various gauge wire. Due to the nature of HDSL
transmission technology, the HDSL lines do not require any special conditioning and may include
unterminated bridge taps, but cannot include load coils.
Table 2. PG-Flex Distances
Loop Length
Wire Gauge
16/32 Channel System
Resistance @ 28
°
C
26 AWG
(0.4 mm)
8.1 kft
(2.5 km)
686
Ω
24 AWG
(0.5 mm)
10.7 kft
(3.3 km)
569
Ω
22 AWG
(0.6 mm)
13.7 kft
(4.2 km)
457
Ω
19 AWG
(0.9 mm)
19.4 kft
(5.9 km)
322
Ω
4.6
Subscriber Drop Testing. For subscriber drop testing from the CO, PG-Flex is able to select and
connect any subscriber drop to a metallic test pair at the RT. PG-Flex extends this connection back to
the COT where technicians can switch it onto a test access bus, or to the corresponding subscriber
line on the COT channel card.
Metallic access is performed from the subscriber’s COT. Refer to the FLC-704 technical practice for
more information.
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