Cisco Model D-PCG1000 PowerKEY CAS Gateway Installation Guide
Chapter 2 Upgrading the QPSK Software
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4012762 Rev D
Example: With 155 km set on the QPSK, the closest distance you could locate a
DHCT to a QPSK modulator is 155 km. The furthest distance you could locate a
DHCT to a QPSK modulator is 217 km.
DHCT to a QPSK modulator is 155 km. The furthest distance you could locate a
DHCT to a QPSK modulator is 217 km.
Network Configuration Application Rules
Follow these application rules when configuring the network for the QPSK ranging-
distance extension mode.
distance extension mode.
Rule Description
1
The QPSK modulator operates normally when no delay value is
configured.
configured.
2
Only four D9482 QPSK Demodulators can be connected to a QPSK
modulator operating in delay mode. These demodulators must be
connected to ATM-25 port locations 5, 6, 7, and/or 8. (Ports 1 through 4
may not be used in the range extension mode.) The configuration at the
DNCS should reflect this requirement.
modulator operating in delay mode. These demodulators must be
connected to ATM-25 port locations 5, 6, 7, and/or 8. (Ports 1 through 4
may not be used in the range extension mode.) The configuration at the
DNCS should reflect this requirement.
3
The programmed delay distance should be less than or equal to the sum of
the transport cable to the hub, plus the shortest optical cable distance on
any of the attached nodes.
the transport cable to the hub, plus the shortest optical cable distance on
any of the attached nodes.
4
The ranging radius is 0 km to 64 km, with 0 km set at the programmed
cable length.
cable length.
5
Transport distances are in integer multiples of 31 km to a maximum of
248 km.
248 km.
6
All four demodulators are delayed by the same value programmed in the
QPSK modulator.
QPSK modulator.
7
The distance ranges stated in this document are approximate and based on
a velocity of propagation in fiber of 68 percent of the speed of light in a
vacuum (3 x 108 meters per second). Corrections to the setting of the
QPSKs should be made where these distances do not apply, as in coaxial
cable.
a velocity of propagation in fiber of 68 percent of the speed of light in a
vacuum (3 x 108 meters per second). Corrections to the setting of the
QPSKs should be made where these distances do not apply, as in coaxial
cable.
8
DHCTs closer than the programmed distance value may not range and
may interfere with other DHCTs.
may interfere with other DHCTs.
9
The delay distances that appear on the front panel of the QPSK are one-
way path distances and assume an equal distance path on the forward and
reverse connection. It is not necessary for the forward and reverse path to
be the same distance as long as the total propagation delay matches the
equivalent time delay.
way path distances and assume an equal distance path on the forward and
reverse connection. It is not necessary for the forward and reverse path to
be the same distance as long as the total propagation delay matches the
equivalent time delay.