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 5V PCI slot in IBM and compatible computers. 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, Windows 95/98/NT will detect it as new hardware and assign it an IRQ number and base address. There are no switches to set or base addresses to assign, making it easy to use. From this point on, the card behaves as standard COM ports at COM 5 and 6. You cannot set or change the card's base address, you can only determine what the system has assigned. The PCI Bus supports 64K of I/O address space so your card's address may be located anywhere in the 0000 to FFFF range.
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Call for PCI-X, 3.3V Compatibility |
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Dual-port serial communications card for PCI bus |
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Supports RS-232(PCI-COM2S only), RS-422, and RS-485 protocols |
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Automatic control of RS-485 driver under Windows systems |
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Includes type 16550 UART with 16-byte FIFO buffers |
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Baud rates up to 460,800 baud |
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Detected as standard COM ports under Windows 9x/NT4/NT2K |
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No base address or IRQ switches to set |
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