PCI-COM2S AND PCI-422/485-2

PCI-COM2S AND PCI-422/485-2
Dual-Port Serial Interface Cards
Universal PCI, PCI-X, 3.3V and 5V compatible
Dual-port serial communications card for PCI
Supports RS-232(PCI-COM2S only), RS-422,
and RS-485 protocols
Automatic control of RS-485 driver under
Windows systems
Includes type 16550 UART with 16-byte FIFO
Baud rates up to 460,800 baud
Detected as standard COM ports under
Windows 9x/NT4/NT2K
No base address or IRQ switches to set
The PCI-COM2S and PCI-422/485-2 are dual-port, asynchronous serial communications cards designed for
use in PCI-Bus computers. They are 6.5 inches (165 mm) long and may be installed in any 3.3V or 5V PCI or
PCI-X slot. Each independent port supports RS-422 and RS-485 balanced-mode transmission/reception, and
on the PCI-COM2S, RS-232 single-ended transmission/reception as well. Each port of the PCI-COM2S and
PCI-422/485-2 has the capability to add bias voltage. (RS-485 communication requires that one transmitter in
the network must supply a bias voltage to ensure a known "zero" state when all transmitters are OFF). Also,
receiver inputs at each end of the network should be terminated to eliminate ringing. The PCI-COM2S and
PCI-422/485-2 support these options by means of jumpers on the card.
Type 16550 UARTs are used as the asynchronous communication elements. These include a 16-byte
transmit/receive FIFO buffer to protect against lost data in multitasking systems while maintaining 100 percent
compatibility with the original IBM serial port. A crystal oscillator is located on the card and permits precise
baud rate capability up to 115,200. Higher baud rates, up to 460,800 baud, are achieved by changing a jumper
on the card. The driver/receivers used, type 75ALS180, are capable of driving extremely long communication
lines at high baud rates. They can drive up to ±60 mA on balanced lines and receive inputs as low as 200 mV
differential signal superimposed on common mode noise of +12V to -7V. In case of communication conflict, the
driver/receivers feature thermal shutdown.
When the card is first installed your operating system should automatically detect and configure the two COM
ports for immediate use.
In RS-485 communications the driver must be enabled when needed and then disabled to permit all cards on
the network to share a two-wire or four-wire cable. The PCI-COM2S and PCI-422/485-2 cards have two
methods to control the driver: automatic (AUTO) and request-to-send (RTS) control. Under automatic control,
the driver is enabled (and the receiver disabled) when data are ready to be transmitted. When transmission is
complete, the driver remains enabled for the transmission time of one additional character and then is
disabled. The card automatically adjusts its timing to the baud rate of the data. (NOTE: For use in half-duplex
mode under Windows, PCI-COM2S must be operated in the AUTO mode.) In the RTS mode, application
software must set a bit to enable the driver and reset that bit to disable the driver.
Return to Product Description
Communications Interface
I/O Connection: 9-pin male D-sub connectors.
Serial Ports: Two shielded male D-sub 9-pin IBM AT style connectors compatible with RS232(PCI-COM2S only), RS-422 and RS-485 specifications.
Character length: 5, 6, 7, or 8 bits.
Parity: Even, odd or none.
Stop Interval: 1, 1.5, or 2 bits.
Serial Data Rates: Up to 115,200 baud, Asynchronous, Asynchronous. A faster range of
rates, up to 460,800 baud, is achieved by jumper selection on the card. Type 16550 buffered
Caution: The OUT2 bit of the UART must be set low for proper interrupt driven communication. This
bit enables or disables the interrupts and the card will not communicate if the bit is pulled high.
RS-232 Drivers(PCI-COM2S Only)
Device: 75C185 Quad Line Transceivers
Output Voltage: ± 6VDC minimum, current limited to 10 mA.
Receiver threshold: 1.5V high, 0.75 low, Maximum input ±30VDC
RS-422/RS-485 Differential Communication Mode
Multipoint: Compatible with RS-422 and RS-485 specifications. Up to 32 drivers and receivers
allowed on line. Serial communications ACE used is type 16550. Driver/Receivers used are
type 75ALS180.
Receiver Input Sensitivity: ±200 mV, differential input.
Common Mode Rejection: +12V to -7V
Transmitter Output Drive Capability: 60 mA, with thermal shutdown.
Operating Temperature Range: 0o to +60 o C
Humidity: 5% to 90%, non-condensing.
Storage Temperature Range: -50o to +120 o C
Power Required: +5VDC at 125 mA typical, -12VDC at 5 mA typical, +12VDC at 5 mA typical,
750 mW total power consumption.
Size: 6 1/2" long (165 mm) by 3 7/8" (99 mm)
Regulatory Compliance
Declaration of Conformity, and Test Reports are on file. Users must use appropriate shielded cables.
Part Number
View / Download PCI-COM2s Manual (in .PDF format)
View / Download PCI-422/485-2 Manual (in .PDF format)
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