Description
The PCL-849 series are four port serial communication interface cards. Each port can be configured individually to RS-232 using on- board jumpers.
PCL-849A/849B serial ports are implemented using 16C554 UARTs which make serial I/O more reliable. For higher performance, 16C654 UARTs can be installed in place of the 16C554 to create the PCL- 849+. By buffering data into 64-byte packets before putting it on the bus, UARTs drastically reduce the CPU load. This makes the PCL-849+ especially suitable for high-speed serial I/O applications under multitasking environments and for applications involving high data rates.
PCL-849 series cards support two operating modes: standard mode and enhanced mode. In standard mode each of the four port addresses can be set individually. In enhanced mode, all four port addresses can be set automatically. The PCL-849+ also supports either shared IRQ or independent IRQ functions. When an on-board interrupt occurs the interrupt status register (vector address) indicates which port generat- ed it. The shared interrupt can be set to most common (extended) AT interrupts. This simplifies programming, speeds interrupt processing and frees interrupts for other devices.
