Black Box MDS920C-10BT, User Manual

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of the incoming signal.
The line interface includes a scheme with integrated into it Digital-to-Analog and Analog-to-Digital
Converters, input and output amplifiers with a programmed amplification and analog filters that
are used to convert digital data into a signal and visa versa.
The device is powered from an in-built 3.3-V or 5-V AC-DC/DC adapter. The input voltage of the
secondary power supply source is 38…72.0 V or 200+/-10% V
AC
.
The network interface unit converts the data signal layers of the device, connected to network
interface and data preprocessing in accordance with the configured operation mode of the
network interface before the data is transmitted onto the chip.
5.2 Operation mode
This part contains the description of different operation modes of the device.
The operation mode can be changed locally from the control computer connected to the device
management interface or remotely over Telnet/HTTP protocols.
5.2.1 G.shdsl line interface
“Master/Slave” mode
To start up a link between two devices, one system must be configured as master and the other
as slave. Moreover, the link start-up is controlled by the COE (Central Office Equipment) unit. It is
impossible to start up a link in the COE-COE or CPE-CPE configuration. The devices are
delivered in the CPE (Customer Premises Equipment) mode (default setting).
Connection at a fixed speed (Fixed Mode)
The devices can communicate at a fixed speed. The line speed adaptation to the line parameters
will not take place, i.e. the communication will be at a fixed speed even if the line allows higher
speeds.
COE is configured for fixed speeds, while CPE is configured for adaptive mode.
Connection with an automatic speed regulation (Adaptive mode)
To simplify the setup, the devices can automatically adjust the line rate, they adapt to the line
quality. The lack of lost packets during the test time is the criterion of the optimal line rate
adjustment.
The adaptive mode is set on both COE and CPE devices.
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