Asynchronous Terminals and Printer Processes Programming Manual

PRINTER PROGRAMMING CONSIDERATIONS
Resetting the 5512 Printers
| SETMODE 29 is the only SETMODE parameter not affected by a
| SETMODE 28 operation or by the RESET command when the device is
| first opened. SETMODE 29 sets auto answer or control answer.
|
| Do not press the RESET button on the printer during printing.
| Doing so can cause data to be lost. Pressing the RESET button
| does not reset programmable parameters or top of form, nor does
| pressing the RESTORE button on the printer.
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| Direct-Access Vertical Format Unit
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| The 5512 printers do not support DAVFU or VFU downloading.
MODEMS
The next few pages describe some special considerations that
apply to communication with printers that are attached to the
host through modems.
Modem Support
| A model 5508, 5520, 5530, 5540, 5573, 5512, 5515/5516 serial
| printer can be used over a phone line using Bell System 103, 113,
| 202, 212, or other full-duplex, asynchronous modems. Two
answering modes are available: automatic answer (the default)
and control answer. Specify AUTOANSWER or CTRLANSWER mode with
SYSGEN or SETMODE 29.
In automatic answer mode, the I/O process asserts both DTR and
RTS. This allows calls from the printer to be answered at any
time. Once the phone has been answered, the application can
write to the printer without any special modem control code,
provided the connection is still good. This allows any program
that can access the printer locally to access it over a modem as
well. In automatic answer mode, the communication line is not
disconnected when the file is closed.
Control answer mode gives the application full control of
answering and hanging up the phone. DTR is not raised until the
application issues CONTROL 11 (answer the phone), which waits for
the modem to connect with the printer. When the file is closed
or the application issues a CONTROL 12 (hang up the phone), DTR
is dropped, and the line is hung up.
7-38 November 1987