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© Sealevel Systems, Inc. 2104 Manual | SL9092 9/2021
Technical Description
The
485I:
utilizes a USB UART. This chip features programmable baud rate, data format, 128-
byte Dual Port RX Buffer, and 256-byte Dual Port TX Buffer. The RS-422/485 transceiver supports data
rates from 300 baud up to 921.6K baud.
Features
•
Hot-Pluggable device
•
Does not require opening the case
•
No system resources are required (i.e., I/O ports or IRQ’s)
•
LED status indicators for “USB Enabled”, “TD”, and “RD”
Connector Pin Assignments (DB25 Male)
The
485I
complies with the EIA-530 pin out with the following signals supported
Signal
Name
Pin #
Mode
GND
Ground
7
RDB
RX+
Receive Positive
16
Input
RDA
RX-
Receive Negative
3
Input
TDB
TX+
Transmit Positive
14
Output
TDA
TX-
Transmit Negative
2
Output
The modem control signals are internally biased as follows: RTS is connected to CTS, DTR is
connected to DCD and DSR, and RI is tied inactive.
