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RS422/485 to RS232 Interface Converter
CAT-285
U User Selectable
RS422 or RS485
U RS485 User Selectable
2 or 4-Wire Operation
U Intelligent Control
of RS485 Transmitter
and Receiver
U Td and Rd LED Indicators
U DTE/DCE Compatible
U Data Rates
up to 64k BPS
SERIAL I/O
CAT285 shown smaller than actual size.
The CAT-285 is a unique interface
converter that can be configured by
the user to convert either RS422 or
RS485 to RS232. When operating
in RS485 mode, the CAT-285 has
an “intelligent” mode which provides
control of the RS-485 line.
When configured to operate as
an RS232 to RS422 interface
converter, the CAT-285 converts
full duplex data, Td and Rd,
between RS232 and RS422.
As an RS232 to RS485 converter,
the unit can be configured for either
2 or 4-wire operation. In either
mode, the CAT-285 allows control of
the transmitter so that multi-dropped
operation can be accommodated.
The CAT-285 can be configured to
control its data flow in one of two
ways. The first is via the use of
RTS, pin 4, of the RS232 port. In
this case, the RS485 transmitter will
turn ON when RTS
is turned on. When RTS is OFF,
the CAT-285 is in the receive mode.
In the 4-wire mode, the receiver is
always on. The second method of
controlling the RS485 transmitter
is to turn it on when Td data is
applied to the RS232 port.
The receiver also operates
differently depending on whether the
mode is 2 or 4-wire. In the 2-wire
mode, when no data is received
by the RS232 receiver, the RS485
receiver is switched ON. When
data is detected for transmission,
the receiver is switched OFF. In the
4-wire mode, the RS485 receiver is
constantly ON while the transmitter
is switched as required.
The CAT-285 is equipped with
a five position dip switch that is
used to select the following:
RS422 mode: 4-wire
RS485 mode: 2-wire
RS485 mode: 4-wire
RS485 mode: controlled by RTS
RS485 mode: controlled by data
220 Ω terminator: in or out
The CAT-285 is also equipped
Connectors: RS232, DB-25 male,
RS422/485, 5-position terminal block
Indicators: 2 LEDs, Td and Rd
Switches: DTE/DCE switch
selectable for reversing
Td and Rd; 5-position dip switch
set RS422/485 operation and
termination
Data Rate: 0 to 64k bps
MTBF: 596,000 hours
Power: 115 Vac at 60 Hz
Dimensions:
0.875 x 2 x 3.5"D
Operating Ambient: 0 to 50°C
(32 to 122°F); 5 to 95% RH,
non-condensing
with a DTE/DCE switch to allow
reversing pins 2 and 3 on the
RS232 interface. Td and Rd LED
indicators help verify operation.
Specifications
Interface: RS232, conforms
to CCITT V.24; pins 2 and 3 (transmit/
receive data) switch selectable, pin
4 (RTS) tied to pin 5 (CTS), pins 6
(DSR), 8 (DCD) and pin 20 (DTR)
are connected together; RS422 or
RS485, selectable
Extended Warranty
Program
OMEGACARESM extended
warranty program is available for
models shown on this page. Ask
your sales representative for full
details when placing an order.
OMEGACARE
labor and equivalent loaners.
SM
SM
covers parts,
To Order
Model No. Description
CAT-285 RS422/485 to RS232 interface converter
Ordering Example: CAT-285, RS422/485 to RS232 converter and OCW-1, OMEGACARE SM
extends standard 1-year warranty to a total of 2 years.
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