Simrad AP48 Operator's Manual page 37

The Device list shows the devices that provide data. This may
include a module inside the unit, or any external NMEA 2000 device.
Selecting a device in this list will bring up additional details and
actions:
All devices allow allocation of an instance number in the Configure
option. Set unique instance numbers on any identical devices on
the network to allow for the unit to distinguish between them. The
Data option shows all data being output by the device.
Some devices will show additional options specific to the device.
Ú Note:
Setting the instance number on a 3rd party product is
typically not possible.
Diagnostics
Provides information useful for identifying an issue with the
network.
Ú Note:
The following information may not always indicate an
issue that can be simply resolved with minor adjustment to
network layout or connected devices and their activity on the
network. However, Rx and Tx errors are most likely indicating
issues with the physical network, which may be resolved by
correcting termination, reducing backbone or drop lengths, or
reducing the number of network nodes (devices).
Bus state
Indicates whether the bus is powered, but not necessarily
connected to any data sources. However, if bus shows as off, but
power is present along with an increasing error count, it is possible
that termination or cable topology is incorrect.
Software setup| AP™ 48 Operator Manual
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