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cent.7 (2010 09)

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cent(7) cent(7)
(Workstations Only)
NAME
cent - Centronics-compatible interface
DESCRIPTION
cent is a simple, widely used communication protocol most commonly associated with printers, plotters
and scanners. It is an eight-bit parallel data interface with additional control signals from the host com-
puter, and status signals from the peripheral.
The
cent interface driver does no character processing; that is, it does not interpret the data being
transferred between computer and peripheral. Therefore, all bytes sent to or received from a device are
handled without alteration. The cent interface driver always operates in raw mode; therefore, any
desired data interpretation must be performed by a user program (such as the ‘‘lp’’ spooler in conjunction
with an appropriate model file). The
cent
driver supports six different handshake modes for data
transfer. The last four bits of the minor number of the device special file specify the mode used. The for-
mat of the device minor number is:
0xII000A
where each letter after the ‘‘0x’’ prefix represents a single hexadecimal digit, as follows:
II Specifies the instance number of the centronic interface.
000 Always zero.
A Specifies the handshake mode. The handshake modes are:
mode 1 Automatic handshaking using both ACK and BUSY.
Minor number format:
0xII0001.
mode 2 Automatic handshaking using only BUSY.
Minor number format:
0xII0002.
mode 3 Bidirectional read/write used for ScanJet.
Minor number format:
0xII0003.
mode 4 Stream mode. Data is essentially transmitted to the peripheral without any
handshaking protocol.
Minor number format:
0xII0004.
mode 5 Pulsed mode using both ACK and BUSY for automatic handshaking. Similar to
mode 1 except that the data strobe line,
nSTROBE, is pulsed for a fixed amount of
time by the sender, then released.
Minor number format: 0xII0005.
mode 6 Pulsed mode, using only BUSY for automatic handshaking. Similar to mode 1
except that the data strobe line,
nSTROBE, is pulsed for a fixed amount of time by
the sender, then released.
Minor number format: 0xII0006.
Modes 1 and 2 support most HP ∗Jet series printers (LaserJet, DeskJet, QuietJet, etc.).
AUTHOR
cent was developed by HP.
SEE ALSO
lp(1), ioctl(2), intro(7), lp(7).
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

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