Comtech EF Data UT-4500 Series - Manual (Page 75)

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Chapter 5.
Remote Control
5.1 G
ENERAL
Each Comtech EF Data series Up Converter can be remotely controlled through a serial
port. Primary (chained) converters in a redundancy subsystem can also be indirectly
controlled through the backup converter using virtual addressing. Comtech EF Data’s
simplified Command/Response protocol is easily invoked by either a monitor and control
computer, a non-intelligent ASCII terminal or a laptop computer operating in terminal
emulation mode. All converter configuration parameters as well as all monitor and status
information is available via the remote port.
The Comtech EF Data converter family has been designed specifically to reduce the cost
and complexity associated with operating in redundancy subsystem configurations. The
backup converter in the redundancy subsystem automatically monitors the configuration
and status for each of the primary (chained) converters. This information is
communicated via the High Speed Bus interface is updated at a polling rate of 1.95
milliseconds per primary converter. If a primary converter fails, the backup detects this
event and automatically reconfigures itself to the proper frequency and attenuation setting
providing minimal loss of traffic on the failed channel.
The result of this design is to greatly reduce the throughput requirements (i.e. polling
rate) of earth station monitor and control systems. The backup converter handles all of
the ‘time critical’ tasks allowing the earth station monitor and control system to focus on
less intelligent subsystems. This document specifies the remote control capabilities of
the converter including hardware configuration and software command structure.
5.2 P
ROTOCOL
5.2.1 T
RANSMISSION
M
ODE
The transmission mode is half duplex implemented in Command/Response convention.
This method requires the external system monitor and control unit to initiate all
communications by command and all converters to respond with either confirmation or
an error message. The confirmation may contain status information.