Access Methods; Direct Access; Indirect Access - Comtech EF Data DT-4572 Installation And Operation Manual

DT4572 X-Band Down Converter
Remote Control
B.3 A
CCESS
Converters may be accessed directly by using a physical address or indirectly through a
backup Converter by using a virtual address.
B.3.1 D A
IRECT
Converters may be directly accessed by the EIA-232C interface or by the EIA-485
interface in a bus configuration.
B.3.1.1 EIA-485
In this control network, all converters including the backup Converter are paralleled on a
common EIA-485 cable. Both up and down converters can be mixed on the cable as long
as each converter has a unique physical address. Only one EIA-485 port is required on
the system's monitor and control computer. If a change is initiated directly to a converter
in a redundancy subsystem, the backup Converter will detect the change via the High
Speed Bus and update its backup tables.
B.3.1.2 EIA-232C
For EIA-232C control, a direct EIA-232C cable connection is made to each converter to
be accessed. If an external Monitor and Control Computer is used, one EIA-232C port
per converter is required. This mode is commonly used with an ASCII terminal for
bench testing.
B.3.2 I
NDIRECT
Converters in Redundancy Mode may be addressed indirectly by adding a virtual address
to the backup Converter's physical address. The virtual address corresponds to
converter's position in the redundant subsystem. The backup Converter recognizes the
virtual address and executes the command via the high speed bus.
B.3.2.1 EIA-485
To control by using the EIA-485 interface, one or more backup Converters are connected
to a system's monitor and control computer or ASCII terminal with a common EIA-485
bus cable. Both up and down backup Converters may be mixed on the cable as long as
each has a unique device address. In order to indirectly address an online converter in the
subsystem, a virtual address must be provided. The virtual address corresponds to the
converter's position in the chain beginning with number 1. Virtual addressing is only
recognized by a backup Converter. Only one EIA-485 port is required on the monitor
and control computer.
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