4 of 6
9/10/2007
#26217
724-746-5500
blackbox.com
IC1600C
With more people using the Internet, new demands have
been placed on computer serial ports. Many PC serial ports
aren’t equipped to handle the level of buffering required for
newer data rates. But advanced UARTs—such as the 16550,
16650, 16750, and 16850—go a long way toward satisfying
the requirements.
I/O addresses and IRQs
All the UARTs in the PCI cards are buffered, so the CPU is
not constantly interrupted to process data.
The adapter is automatically assigned I/O addresses and
IRQs by the motherboard BIOS. Only the IRQ address can be
modified by the user.
16550 UART
Used in the IC133C-R2 and IC141C-R2, the 16550 features a
16-byte input and output First-In, First-Out (FIFO) buffer that
holds characters for the transmitter and receiver. The FIFO
enables you to obtain higher data rates while reducing the
frequency of processor interrupts. It supports sustained data
rates up to 115.2 kbps or bursts of data up to 460.8 kbps.
16554 UART
Used in the IC142C, two 16554 UARTs contain four 16550
UARTs, each with a 16-byte FIFO buffer.
16650 UART
Used in the IC140C-R2, the 16650 UART features a 32-byte
FIFO buffer and can handle sustained data rates up to
460.8 kbps. But you must use the appropriate line drivers and
receivers and be able to optimize the other factors that affect
performance (such as CPU, number of ports, cable length and
quality, and electrical interface).
16654 UART
Used in the IC132C-HS, two 16654 UARTs contain four
16650 UARTs, each with a 32-byte FIFO buffer.
16750 UART
Used in the IC143C-R2, the 16750 has a 64-byte FIFO buffer.
It also features sustained baud rates of 460.8 kbps but delivers
better performance because of its larger buffer.
16850 UART
Used in the IC970C-LP, IC971C, IC975C-LP, ICR975C-LP,
IC972C-R2, IC187C-LP, IC973C–IC974C, IC187C, and IC189C, the
16850 UART has a 128-byte FIFO buffer for each port.
The 16850 UART features FIFO UARTs that enhance
communications. They help you avoid the many I/O
problems—like data overruns or underruns—that occur in
a multitasking environment when the UART buffering isn’t
large enough to handle the incoming data. These, of course,
can interrupt performance and affect your communications.
The 16850 chip also supports an isochronous scheme,
which is asynchronous framing with the addition of clock
signal. This scheme allows for much higher data rates and
the use of a digital line (ISDN, T1) where a clock is supplied
for data multiplexing. And you can get high-speed
communications with a simple communications interface
that responds to standard communication calls.
16854 UART
Used in the IC188C-R2, IC190C-R2, and IC1600C, the two
16854 UARTs contain four 16850 UARTs, each with a 128-byte
FIFO buffer.
16C864 UART
Used in the IC978C, the two 16C864 UARTs contain four
16860 UARTs. Each UART has a 128-byte FIFO buffer.
Technically Speaking
