Asynchronous Terminals and Printer Processes Programming Manual

PRINTER I/O
Flow Control Characteristics
detector (SCF). The controller then delays transmission until
the device drops SCF.
For REVTPAUSE the device must drop and then raise SCF. These
modems require request to send (RTS) to drop when switching
from transmit to receive. SDCD must be high to the DCE when
receiving. REVTPAUSE is available only for ATP6100 subdevices.
ATP6100 does not check the transfer size (XFERSIZE) specified
by SYSGEN. TPAUSE or REVTPAUSE and CTS flow control cannot be
active at the same time. The REVTPAUSE modifier indicates the
presence of a half-duplex, Bell 202-type modem.
Table 5-3 summarizes the characteristics of TPAUSE and REVTPAUSE.
Table 5-3. TPAUSE and REVTPAUSE
SCF signal (pin 12) TPAUSE REVTPAUSE
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Logical 1, on, space Pause Transmit
Logical 0, off, mark Transmit Pause
Form Control Characteristics
Form control characteristics control the movement of the paper
through the printer. Table 5-4 summarizes the form control
parameters and how to change them. The parameters are described
in detail below.
November 1987 5-7