Four RS-422/485 Ports on One PC Card
Serial PCMCIA PC cards are a flexible, low-cost interface that allows you to
gather industrial and scientific data and control remote serial devices with
laptop computers that lack serial ports.
Our COMR 4422C Type II card is small and light--and provides speeds up to
115.2 kbps. It typically draws 45mA to conserve battery energy; maximum power
draw is 55mA. All our COMR PCMCIA cards are PCMCIA PC Card Standard
Specification 2.1 compliant.
Each COMR card provides four fully independent ports. On the COMR 4422C, each
port can be configures as RS-485 by connecting a 60-ohm resistor at each end of
the circuit or as RS-422 by using a 100-ohm resistor at the receiver end. Both
cards feature 16550 UARTs that provide 16-byte transmit and receive FIFOs for
each port. Software-definable port addresses must be set at even 32-byte (20H)
RS-422/485 ports default to full duplex operation, but can be configured for
half-duplex via software (which is included FREE with each COMR card). Only
point-to-point communication is supported in half-duplex configurations.