Electroline Control Unit IV, Справочное руководство

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Product Description Control Unit IV Reference Manual
1-10 529-0004 Ver.3
Important:
Do not modify or change the components on the motherboard. Only replace the backup
battery and the fuse or add expansion boards as needed.
Expansion slots
The Control Unit has three expansion slots on the motherboard. On current models, the
RAM Expansion Board (see RAM section below) is preinstalled in the central expansion
slot. The two remaining slots have identical connectors, but different space availability: the
slot on the left accepts a larger board.
RAM
The Control Unit has 256 KB of RAM on board. Part of the Control Unit’s memory is used
to store the status of the subscribers, the TPS units or the CPMs, and the other part is used to
execute programs that switch the subscriber’s tap or the return path, or that carry out various
internal tests.
The plug-in RAM Expansion Board installed in the Control Unit provides an additional
1 MB of RAM. The additional memory gained with the RAM board can be used to support
special features such as churn analysis. If this board is not already installed, contact your
Electroline representative to place an order.
Battery
The Control Unit uses a lithium 3 VDC (CR2430 or CR2450) battery to maintain the
subscriber status information in the Control Unit’s RAM in case there is a power failure.
You must replace this battery about every two or three years, or when the battery LED on the
front panel is lit (see Chapter 5).
FSK modulator and demodulator
There are two kinds of modulators that produce an FSK carrier used by the Electroline
decoders deployed in the cable plant: dual FSK and single FSK.
Control Unit’s with a dual FSK modulator modulate the control carriers on two frequencies
in order to represent the binary elements of a data stream coming from the sequencer. The
nominal carrier frequency is indicated on the label near the RF output on the unit’s rear
panel.
Control Unit’s with a single FSK modulator are frequency agile over a given range, as shown
on the frequency range label next to the RF output on the unit’s rear panel. Since these units
are frequency agile, the carrier frequency shown on the rear panel may change. You can
check the frequency by using the Workabout to read the carrier (see the Electroline
Programmer/Monitor (EAS-PMW) User Guide for more details).
The Control Unit’s demodulator operates in the same way as the demodulators in the
Electroline addressable equipment deployed in the cable plant. The demodulator verifies the
presence and integrity of the signal that the Control Unit transmits to the cable network.