Lenovo PC 300GL Understanding Your Personal Computer 6267, 6277, 6287 - Page 28

Parallel Port, Configuration/Setup Utility Program.

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Parallel Port Your computer has a parallel-port connector as a standard, built-in feature. The parallel port is most often used to communicate with a parallel printer, but it can also be used with a variety of other parallel devices. The parallel port transfers data 8 bits at a time, compared to the serial port, which transfers data 1 bit at a time. The parallel port on the computer supports extended, high-speed modes, which means that it can transfer data up to 10 times as fast as a standard parallel port. You can increase the number of parallel connectors by installing a parallel adapter in one of the expansion slots. Operating systems and application programs often designate parallel ports with the name LPT (line printer). Many programs use LPT1, LPT2, and LPT3 in their setup commands or menus to identify parallel ports. When setting up your applications, you might have to identify the LPT port to which a particular device is connected. Also, if you are adding a parallel adapter, you might have to configure the adapter for a specific LPT port. This might involve setting switches on the adapter as well as changing settings in the Configuration/Setup Utility Program. Each parallel connector or adapter on your computer can use any of three available port settings, provided that a different setting is used for each. The settings include the port address (in hexadecimal) and the IRQ (interrupt request line), which determines how the microprocessor responds to an interrupt from the parallel port. The three available port addresses are (in hex) 378 278 3BC The two available IRQs are: IRQ 7 IRQ 5 There is no direct relationship among the three available port settings and the three LPT numbers. When you start the computer, the POST assigns LPT numbers to the port addresses that are actually in use at the time. POST goes down the list of addresses sequentially to assign LPT numbers to each address in use by a parallel device. If an address is not in use, an LPT number is not assigned to it. POST assigns the next available LPT number to the next address in use, if any. You can view the port address and IRQ setting for the built-in parallel port using the Configuration/Setup Utility Program. However, you will not see the LPT number on the configuration screen. To see port settings and LPT assignments for all parallel ports, you 20 I/O Features

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Parallel Port
Your computer has a parallel-port connector as a standard, built-in feature.
The parallel
port is most often used to communicate with a parallel printer, but it can also be used with
a variety of other parallel devices.
The parallel port transfers data 8 bits at a time, compared to the serial port, which transfers
data 1 bit at a time.
The parallel port on the computer supports extended, high-speed
modes, which means that it can transfer data up to 10 times as fast as a standard parallel
port.
You can increase the number of parallel connectors by installing a parallel adapter in one of
the expansion slots.
Operating systems and application programs often designate parallel ports with the name
LPT
(
line printer
).
Many programs use
LPT1
,
LPT2
, and
LPT3
in their setup commands or
menus to identify parallel ports.
When setting up your applications, you might have to
identify the LPT port to which a particular device is connected.
Also, if you are adding a
parallel adapter, you might have to configure the adapter for a specific LPT port.
This
might involve setting switches on the adapter as well as changing settings in the
Configuration/Setup Utility Program.
Each parallel connector or adapter on your computer can use any of three available port
settings, provided that a different setting is used for each.
The settings include the port
address
(in hexadecimal) and the
IRQ (interrupt request line)
, which determines how the
microprocessor responds to an interrupt from the parallel port.
The three available port addresses are (in hex)
378
278
3BC
The two available IRQs are:
IRQ 7
IRQ 5
There is no direct relationship among the three available port settings and the three LPT
numbers.
When you start the computer, the POST assigns LPT numbers to the port
addresses that are actually in use at the time.
POST goes down the list of addresses
sequentially to assign LPT numbers to each address in use by a parallel device.
If an
address is not in use, an LPT number is not assigned to it.
POST assigns the next available
LPT number to the next address in use, if any.
You can view the port address and IRQ setting for the built-in parallel port using the
Configuration/Setup Utility Program.
However, you will not see the LPT number on the
configuration screen.
To see port settings and LPT assignments for all parallel ports, you
20
I/O Features