Impulse PC_104 RS‑232, RS‑422, RS‑485 (Software Selectable) Serial Interface (3540) - Manual

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PC/104 ‑ Asynchronous Serial
Item #
The 3540 is the first PC/104 serial interface module
to provide four software‑selectable RS‑232, RS‑422, or
RS‑485 ports. RS‑232, RS‑422, or RS‑485 mode may be
selected independently via software command for each of
the four ports, eliminating the need for setting jumpers or
DIP switches. The board is designed using the XR16C864
UART, which provides a 128‑byte FIFO, 8 times larger
than boards designed with 16C550 compatible parts. The
larger buffers allow error free operation even in high‑speed
applications. In RS‑485 mode the C4‑104.ULTRA offers
automatic control of the RS‑485 driver enable for trouble
free network master arbitration. Additionally, the C4‑104.
ULTRA allows RS‑485 network termination, critical to robust
multi‑drop communication, to be selectively added to the
circuit via a simple software command.
Unique Features
Each port software selectable for RS‑232, RS‑422, or
RS‑485
16C864 buffered UART with 128‑byte FIFOs
Data rates to 921.6K bps
Automatic RS‑485 enable/disable
Termination, pull‑ups, and pull‑down resistors for each
port are software selectable
Right‑angle connector available for OEM opportunities,
40‑pin vertical header connector standard
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Technical Specifications
Communications chip 16C864
Number of ports 4
Max data rate 921.6K bps
Max data distance 4000 feet
Connector 40‑Pin Header
Operating temperature 0 ‑ +70° C
Storage temperature ‑50 ‑ +105° C
Humidity range 10 ‑ 90% R.H.
PC/104 RS‑232, RS‑422, RS‑485 (Software Selectable) Serial Interface
3540