Muratec F-110 Field Engineering Manual page 53

Circuit Description
4-1-7 HOST INTERFACE:
Parallel Port Interface
PARALLEL PORT INTERFACE PART KS32C61100 has the Parallel Port Interface Part that enables Parallel Interface with PC.
This part is connected to PC through Centronics connector. It generates major control signals that are used to actuate parallel
communication. It is comprised of/ERROR, PE, BUSY, /ACK, SLCT, /INIT, /SLCTIN, /AUTOFD and /STB. This part and the PC
data transmission method support the method specified in IEEE P1283 Parallel Port Standard
(http://www.fapo.com/ieee1284.html).
In other words, it supports both compatibility mode (basic print data transmitting method), the nibble mode (4bit data; supports
data uploading to PC) and ECP (enhanced capabilities port: 8bits data - high speed two-way data transmission with PC).
Compatibility mode is generally referred to as the Centronics mode and this is the protocol used by most PC to transmit data
to the printer. ECP mode is an improved protocol for the communication between PC and peripherals such as printer and scan-
ner, and it provides high speed two-way data communication. ECP mode provides two cycles in the two-way data transmis-
sion; data cycle and command cycle. The command cycle has two formats; Run-Length Count and Channel Addressing. RLE
(Run-Length Count) has high compression rate (64x) and it allows real-time data compression that it is useful for the printer
and scanner that need to transmit large raster image that has a series of same data. Channel Addressing was designed to
address multiple devices with single structure. For example, like this system, when the fax/printer/scanner have one structure,
the parallel port can be used for other purposes while the printer image is being processed.This system uses RLE for high
speed data transmission. PC control signals and data send/receive tasks such as PC data printing, high speed uploading of
scanned data to PC, upload/download of the fax data to send or receive and monitoring the system control signal and overall
system from PC are all processed through this part.
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