Configuring Systems for Terminals, Printers, and Other Serial Devices (32022-90051)

Chapter 7 117
Terminal and Printer Profiles
What is a Profile
Printer type 18 responds to an XOFF character sent from a printer. The
XOFF protocol stops the flow of data to the printer so data cannot be
lost. However, the printer cannot send an XOFF character if it is
unplugged, turned off, or loses power. In these instances, data is lost.
Printer Type 21
Use printer type 21 for remote spooled printers. These are
asynchronous printers that can use the MPE/iX spooler.
Printer type 21 uses the XON/XOFF protocol and status checking.
Status checking means an HP printer that respond to the interrogation
string:
[Esc] ? [DC1].
In addition, data transmission errors can be detected (but not
corrected) using parity checking.
Printer Type 22
Use printer type 22 for local spooled printers. These are asynchronous
printers that can use the MPE/iX spooler, but not with modems.
Printer type 22 supports the same data protection methods (the
XON/XOFF protocol and status checking) as printer type 21, except for
parity checking.
Printer Type 26
Use printer type 26 for remote spooled printers connected to a network.
These are printers that can be spooled and connected through a modem
to a statistical multiplexer or printers connected to a PAD. Printer
type 26 builds on printer type 22, with additional features to cope with
delays that occur over a buffered connection.
The status request is sent and the time begins. If there is no reply, the
timer is reset. This is repeated 10 times.
If the status request detects an error condition, for example the printer
runs out of paper, a system console message is displayed and the retry
is done only one more time. If there is no reply or an error occurs, the
connection is closed and the spooler stopped.
The XOFF timer is also retried 10 times. After the last entry, the
connection shuts down and data is refused. In addition to status
request and XOFF changes, all closed connection requests from the
computer are not acted upon for 10 seconds. This avoids having to
reestablish the remote connection if another spoolfile becomes ready to
print before the 10 second wait expires.