Acorn Computers Limited BBC A, Руководство по оборудованию, Страница: 9 / 47

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The parallel printer port can interface with a large number of different printers, including Epson, NEC, and
Seikosha.
The 1MHz bus is used to interface the microcomputer to a whole range of slower peripheral devices such
as EPROM programmers, input output rack systems, data acquisition systems etc.
The "User Port" provides the machine with an eight bit wide input/output connection which can be used to
control external equipment such as robots and relays etc.
The Acorn "Tube" interface is used to allow the BBC Microcomputer to access a second high-speed
microcomputer called a second processor. By adding a second processor to the standard machine the
overall computing power can be greatly enhanced. The resulting improvement will depend upon the
particular second processor. At the present time there are only two second-processor boards available
these are the Z80 and a 3MHz version of the 6502. The Z80 processor will enable the BBC
Microcomputer to use the C/PM operating system and thus enable the machine to run an extremely wide
range of currently available software.
The Acorn "Econet" network feature enables up to 255 BBC Microcomputers to be connected together
and each microcomputer can have access to a central information storage and retrieval device. This
system enables a large number of users to share expensive peripheral devices and also provides each
one with the facility to communicate with any other user in the network. The "Econet" system finds most
use in schools and colleges.
The analogue port, which is located at the rear of the machine, (model B only) allows the user to connect
up to four analogue signals into the computer. These signals could be derived from all manner of
transducers thus enabling the machine to measure and record real physical quantities. This feature will
enable the machine to be used for monitoring signals in experimental or perhaps industrial applications.
The RS423 port situated at the rear of the machine (model B only) enables the microcomputer to
communicate with other pieces of equipment. This equipment could be peripheral devices such as serial
printers or perhaps other computers. In most cases the RS423 port can interface with other equipment
which uses the more common RS232C (V24) serial interface standard, although this is not always the
case. The BBC Microcomputer does not provide all of the signals necessary for a full implementation of
the RS423 standard but the main signal lines are provided. The machine’s operating system enables the
port to be configured for a whole range of baud rates ranging from 75 to 19200 although the integrity of
the data is not guaranteed at 19200 baud.