Black Box Explains...Low-profile PCI serial adapters.
Ever notice that newer computers are getting smaller and slimmer? That means regular PCI boards wont fit into these computers low-profile PCI slots. But because miniaturization is the rage in... more/see it nowall matters of technology, it was only a short matter of time before low-profile PCI serial adapters became available—and Black Box has them.
Low-profile cards meet the PCI Special Interest Group (PCI-SIG) Low-Profile PCI specifications, the form-factor definitions for input/output expansion. Low-Profile PCI has two card lengths defined for 32-bit bus cards: MD1 and MD2. MD1 is the smaller of the two, with cards no larger than 4.721 inches long and 2.536 inches high. MD2 cards are a maximum of 6.6 inches long and 2.536 inches high.
BLACK BOX® Low-Profile Serial PCI cards comply with the MD1 low-profile specification and are compatible with the universal bus. Universal bus is a PCI card that can operate in either a 5-V or 3.3-V signaling level system. collapse
Black Box Explains...IRQs, COM Ports, and Windows
Product Data Sheets (pdf)...Relay/Digital I/O Cards, PCI
Product Data Sheets (pdf)...PC Plus Adapters
Product Data Sheets (pdf)...PCI Fiber Adapters
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
PCI Fiber Adapters, SC
Installation and User Guide (Jul-05)
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…Fiber Ethernet adapters vs. media converters.
When running fiber to the desktop, you have two choices for making the connection from the fiber to a PC: a fiber Ethernet adapter or a media converter like our... more/see it nowMicro Mini Media Converter.
Fiber Ethernet adapters:
Create no desktop clutter, but the PC must be opened.
Powered from the PC—require no separate power provision.
Require an open PCI or PCI-E slot in the PC.
Can create driver issues that must be resolved.
May be required in high-security installations that require a 100% fiber link to the desktop.
No need to open the PC but can create a cluttered look.
Powered from an AC outlet or a PC’s USB port.
Don’t require an open slot in the PC.
Plug-and-play installation—totally transparent to data, so there are no driver problems; install in seconds.
The short copper link from media converter to PC may be a security vulnerability. collapse
Black Box Explains...UARTs and PCI buses.
Product Data Sheets (pdf)...PCI Cards
Universal Asynchronous Receiver/Transmitters UARTs are designed to convert sync data from a PC bus to an async format that external I/O devices such as printers or modems use. UARTs insert... more/see it nowor remove start bits, stop bits, and parity bits in the data stream as needed by the attached PC or peripheral. They can provide maximum throughput to your high-performance peripherals without slowing down your CPU.
In the early years of PCs and single-application operating systems, UARTs interfaced directly between the CPU bus and external RS-232 I/O devices. Early UARTs did not contain any type of buffer because PCs only performed one task at a time and both PCs and peripherals were slow.
With the advent of faster PCs, higher-speed modems, and multitasking operating systems, buffering (RAM or memory) was added so that UARTs could handle more data. The first buffered UART was the 16550 UART, which incorporates a 16-byte FIFO (First In First Out) buffer and can support sustained data-transfer rates up to 115.2 kbps.
The 16650 UART features a 32-byte FIFO and can handle sustained baud rates of 460.8 kbps. Burst data rates of up to 921.6 kbps have even been achieved in laboratory tests.
The 16750 UART has a 64-byte FIFO. It also features sustained baud rates of 460.8 kbps but delivers better performance because of its larger buffer.
Used in newer PCI cards, the 16850 UART has a 128-byte FIFO buffer for each port. It features sustained baud rates of 460.8 kbps.
The Peripheral Component Interconnect (PCI®) Bus enhances both speed and throughput. PCI Local Bus is a high-performance bus that provides a processor-independent data path between the CPU and high-speed peripherals. PCI is a robust interconnect interface designed specifically to accommodate multiple high-performance peripherals for graphics, full-motion video, SCSI, and LANs.
A Universal PCI (uPCI) card has connectors that work with both a newer 3.3-V power supply and motherboard and with older 5.5-V versions. collapse