Specifications

2 PCL-846/847 User's Manual
Description
PCL-846/847 series cards provide four independent RS-422/485 serial
ports on a card. Each port has a 16C550 UART with an on-chip 16-
byte FIFO buffer for reliable, high-speed serial I/O. The UART
buffers data into 16-byte packets before putting it on the bus. This
drastically reduces the CPU load and avoids data loss when the system
is busy and cannot process the interrupt quickly. The UART is
especially useful for high speed serial I/O under Windows.
PCL-846 cards differ from PCL-847 cards in that they utilize on-
board optical isolators to protect your PC and equipment against
damage from ground loops, increasing system reliability in harsh
environments. To further increase reliability, PCL-846B/847B cards
include surge protection technology, protecting your system from
abrupt high voltage surges (up to 2000 V). The PCL-846/847 series
has passed the CE test for environmental specifications.
An RS-485 Network with Automatic Data Flow Control Using RS-232
Software
The RS-485 mode automatically senses the direction of incoming data
and switches its transmission direction accordingly. This feature
means your network looks and acts just like an RS-232 network.
Application software written for half duplex RS-232 can be used
without modification. Moreover, you can simply and quickly build an
RS-485 network with just two wires.
Features
• Four independent RS-422/RS-485 serial ports
• Transmission speeds up to 921.6 Kbps
• Shared/Independent IRQ settings between each of the 4 serial ports
• Wide IRQ selection: 3, 4, 5, 6, 7, 9, 10, 11, 12 or 15
• Supports standard DOS COM1, COM2, COM3, and COM4
• Supports DOS/Windows 3.1 (PC-ComLIB), Windows 95, Windows NT
(ICOM Utility)
• Provides 1000 V
DC
isolation (PCL-846A/846B only)