Simrad SH90 Manuel D'installation page 193

RS-422 is also specified for multi-drop applications. This means that one transmitter can
send data to up to 10 receivers.
Note
There are no common standard for RS-422 pin configuration. Any manufacturer may
choose their own connector pins for the various signals used. In order to make the
RS-422 connection to your peripheral device work properly, you must always consult the
relevant instructions provided by the device manufacturer.
For more information about the RS-422 serial communication standard, see (for
example):
• https://en.wikipedia.org/wiki/RS-422
Interface série RS-485
RS-485 (also known as TIA-485–A) is a standard defining the electrical characteristics
of drivers and receivers for use in balanced digital multipoint systems. The standard
is published by the Telecommunications Industry Association/Electronic Industries
Alliance (TIA/EIA). Digital communications networks implementing the RS-485
standard can be used effectively over long distances and in electrically noisy
environments. Multiple receivers may be connected to such a network in a linear,
multi-drop configuration.
RS-485 offers data transmission speeds of 35 Mbit/s up to 10 m and 100 kbit/s at 1200
m. Since it uses a differential balanced line over twisted pair (like RS-422), it can span
relatively large distances (typically up maximum 1200 m). In contrast to RS-422, which
has a single driver circuit which cannot be switched off, RS-485 drivers need to be put
in transmit mode explicitly by asserting a signal to the driver. This allows RS-485 to
implement linear bus topologies using only two wires. The equipment located along a
set of RS-485 wires are interchangeably called nodes, stations or devices.
RS-485, like RS-422, can be made full-duplex by using four wires. Since RS-485 is a
multi-point specification, however, this is not necessary in many cases.
Note
There are no common standard for RS-485 pin configuration. Any manufacturer may
choose their own connector pins for the various signals used. In order to make the
RS-485 connection to your peripheral device work properly, you must always consult the
relevant instructions provided by the device manufacturer.
For more information about the RS-485 serial communication standard, see (for
example):
• https://en.wikipedia.org/wiki/RS-485
419050/A
Disposition des câbles et interconnexions
191