Black Box Explains...UARTs at a glance.
Universal Asynchronous Receiver/Transmitters (UARTs) are integrated circuits that convert bytes from the computer bus into serial bits for transmission. By providing surplus memory in a buffer, UARTs help applications overcome... more/see it nowthe factors that can hinder system performance, providing maximum throughput to high-performance peripherals without slowing down CPUs.
Early UARTs such as 8250 and 16450 did not include buffering (RAM or memory). With the advent of higher-speed devices, the need for UARTs that could handle more data became critical. The first buffered UART was the 16550, which incorporates a 16-byte First In First Out (FIFO) buffer and provides greater throughput than its predecessors.
Manufacturers have been developing enhanced UARTs that continue to increase performance standards. These faster chips provide improvements such as larger buffers and increased speeds. Here are the rates of todays common UARTs:
UART FIFO Buffer Rate Supported
16550 16-byte 115.2 kbps
16554 16-byte 115.2 kbps
16650 32-byte 460.8 kbps (burst rate)
16654 64-byte 460.8 kbps (burst rate)
16750 64-byte 460.8 kbps (burst rate)
16850 128-byte 460.8 kbps (sustained rate)
16854 128-byte 460.8 kbps (sustained rate) collapse
Black Box Explains... G.703.
G.703 is the ITU-T recommendation covering the 4-wire physical interface and digital signaling specification for transmission at 2.048 Mbps (E1). G.703 also includes specifications for U.S. 1.544-Mbps T1 but is... more/see it nowstill generally used to refer to the European 2.048-Mbps transmission interface. collapse
USB Hub Drivers
Drivers for the IC1020A, IC1022A, IC1023A, IC1025A, IC1026A, & IC1027A
Black Box Explains...How computer speeds are enhanced with PCI buses and UARTs.
The Peripheral Component Interconnect (PCI®) Bus enhances both speed and throughput. The PCI Local Bus is a high-performance bus that provides a processor-independent data path between the CPU and high-speed... more/see it nowperipherals. PCI is a robust interconnect interface designed specifically to accommodate multiple high-performance peripherals for graphics, full-motion video, SCSI, and LANs.
UARTs (Universal Asynchronous Receiver/ Transmitters) are integrated circuits that convert bytes from the computer bus into serial bits for transmission. By providing surplus memory in a buffer, UARTs help your applications overcome the factors that slow down your system. collapse
Black Box Explains...IRQs, COM Ports, and Windows
Product Data Sheets (pdf)...Interface-Powered Converters
Windows® 95 normally requires each serial port to have its own unique Interrupt Request Line (IRQ). However, if you use a third-party communications driver that supports IRQ sharing, you can... more/see it nowshare interrupts. Unfortunately, data throughput will not be as high as with single interrupt port configurations.
With Windows NT®, you can share interrupts across multiple ports as long as the serial ports have an Interrupt Status Port (ISP) built into the card.
The Interrupt Service Routine, a software routine that services interrupts and requests processor time, reads the ISP and is immmediately directed to the port that has an interrupt pending. Compared to the polling method used if the serial ports don’t have an ISP, this feature can determine which port generated the interrupt up to four times more efficiently—and it almost eliminates the risk of lost data. Windows NT supports the ISP by enabling the user to configure the registry to match the card’s settings. Black Box models IC102C-R3, IC058C, and IC112C-R3 all have ISPs and come with a Windows NT setup utility to simplify installation and configuration.
If your serial port doesn’t have an ISP, the Interrupt Service Routine has to poll each port separately to determine which port generated the interrupt. collapse
Product Data Sheets (pdf)...T1 and T3 Rate Converters
Product Data Sheets (pdf)...Communications Adapter Plus (CAP) User-Programmable Communications Adapter Plus (CAP)
Async RS232 to RS-422 Interface Bidirectional Converter, DB9 Female to DB9 Female, User Manual
User Manual for the IC1474A-F