Revision 02
January 12, 1998
Section 363-704-102-02
PG-Flex FLC-704 List 2
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 32 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.
4.7
Metallic access is performed by momentarily p116 Vdc (from the CO) on the subscriber’s
Tip lead. (The Ring lead should be between GND and the Tip value.) Depending on the PG-Flex
system configuration, the selected subscriber drop (assuming a working metallic bypass pair)
connects to the corresponding COT subscriber line.
4.8
The metallic connection drops when -116 Vdc is momentarily applied to the subscriber’s COT Tip.
4.9
Metallic access may also be activated through and ASCII terminal connected to the RS-232 Craft
Maintenance port located on the front of the FLL-716 line unit or through the FAU-728 or FPI-729
units.
Summary of Contents for PG-Flex 8 FLC-704
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