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10. Commands for Printer Devices
10.1. Model for Printer Devices
This command set includes capability for the printer-controlling device,
which is an SCSI target to be is functionally separate from the physical
printer device (see Figure 10-1) as well as integrated with it. The physical
printer device is connected to the SCSI target via one of several common
device-level interfaces. There may be more than one physical printer device
attached to the printer controlling device. In such a case, each physical
printer device is assigned a separate logical unit number, beginning with
zero. The printer-controlling device, printer device-level interface, and the
physical printer device are collectively referred to as the printer device.
--------------- ------------
| | | |
----------| Printer- | Printer Device- | Physical |
SCSI Bus | Controlling |-----------------| Printer |
----------| Device | level Interface | Device |
| | | |
--------------- ------------
Figure 10-1: SCSI Printer Model
Specific control mechanisms are defined in mode pages for two industry-
standard interfaces known as the line printer interface (e.g., the Data
Products interface or equivalent) and the EIA RS-232C interface. These mode
pages are used to control optional features of these interfaces. No mode page
was defined for the popular industry-standard parallel interface because the
options requiring controls are embedded in the data.
The printer-controlling device may be physically integrated within the
printer device and it is not required to use one of the industry-standard
interfaces referenced above.
The printer device commands are structured on the assumption that specific
printer control codes may be embedded in the data transferred by the FORMAT,
PRINT, and SLEW AND PRINT commands. The transparent control codes may take
the form of "escape code sequences". Commands for the operation of the target
function and some printer controls, which are not convenient to handle in a
transparent way, are specified in 10.2.
This standard does not specify which character set is used by the printer
device nor does it specify the meaning of the "escape code sequences" that may
be used.
10.2. Commands for Printer Devices
The commands for printer devices shall be as shown in Table 10-1.
Table 10-1: Commands for Printer Devices
==============================================================================
Operation
Command Name Code Type Section Page
------------------------------------------------------------------------------
CHANGE DEFINITION 40h O 7.2.1
COMPARE 39h O 7.2.2
COPY 18h O 7.2.3
COPY AND VERIFY 3Ah O 7.2.4
FORMAT 04h O 10.2.1
INQUIRY 12h M 7.2.5
LOG SELECT 4Ch O 7.2.6
LOG SENSE 4Dh O 7.2.7
MODE SELECT(6) 15h O 7.2.8
MODE SELECT(10) 55h O 7.2.9
MODE SENSE(6) 1Ah O 7.2.10
MODE SENSE(10) 5Ah O 7.2.11
PRINT 0Ah M 10.2.2
READ BUFFER 3Ch O 7.2.12
RECEIVE DIAGNOSTIC RESULTS 1Ch O 7.2.13
RECOVER BUFFERED DATA 14h O 10.2.3
RELEASE UNIT 17h M 9.2.9
REQUEST SENSE 03h M 7.2.14
RESERVE UNIT 16h M 9.2.10
SEND DIAGNOSTIC 1Dh M 7.2.15
SLEW AND PRINT 0Bh O 10.2.4
STOP PRINT 1Bh O 10.2.5
SYNCHRONIZE BUFFER 10h O 10.2.6
TEST UNIT READY 00h M 7.2.16
WRITE BUFFER 3Bh O 7.2.17
==============================================================================
Key: M = Command implementation is mandatory.
O = Command implementation is optional.
The following operation codes are vendor specific: 01h, 02h, 05h, 06h, 07h,
08h, 09h, 0Ch, 0Dh, 0Eh, 0Fh, 11h, 13h, 19h, and C0h through FFh. All
remaining operation codes for printer devices are reserved for future
standardization.
10.2.1. FORMAT Command
Table 10-2: FORMAT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (04h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Format Type |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | Transfer Length |
-----|--- ---|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The FORMAT command (Table 10-2) provides a means for the initiator to
specify forms or fonts to printers that support programmable forms or fonts.
The format information is peripheral-device specific.
The format type field specifies the type of format information to be
transferred from the initiator to the target. This field is defined as
follows:
DB(1) DB(0) Format Type
----- ----- -------------
0 0 Set Form
0 1 Set Font
1 0 Vendor Unique
1 1 Reserved
The transfer length specifies the length in bytes of format information that
shall be transferred during the DATA OUT phase. A transfer length of zero
indicates that no format information shall be transferred. This condition
shall not be considered as an error.
10.2.2. PRINT Command
Table 10-3: PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (0Ah) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | Transfer Length |
-----|--- ---|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The PRINT command (Table 10-3) transfers the specified number of bytes from
the initiator to the target to be printed.
The transfer length specifies the length in bytes of data that shall be
transferred during the DATA OUT phase. A transfer length of zero indicates
that no data shall be transferred. This condition shall not be considered as
an error.
10.2.3. RECOVER BUFFERED DATA Command
Table 10-4: RECOVER BUFFERED DATA Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (14h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | Transfer Length |
-----|--- ---|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The RECOVER BUFFERED DATA command (Table 10-4) returns to the initiator data
that has been previously transferred to the target, but not yet printed.
This command is normally used only to recover from error or exception
conditions that make it impossible to print the buffered data. The order in
which data are transferred from the target to the initiator is the same as
when the data were previously transferred using the PRINT command or SLEW AND
PRINT command. Data transferred by this command are deleted from the target
data buffer. One or more RECOVER BUFFERED DATA commands may be used to return
the buffered data that is not printed.
If an attempt is made to recover more data than is contained in the buffer,
the command shall be terminated with CHECK CONDITION status and the sense key
shall be set to NO SENSE. In addition, the EOM, valid, and ILI bits shall be
set to one. The information bytes shall be set to the difference (residue)
between the transfer length and the actual number of bytes returned.
The transfer length specifies the maximum length in bytes of data that shall
be transferred during the DATA IN phase. A transfer length of zero indicates
that no data shall be transferred. This condition shall not be considered as
an error.
10.2.4. SLEW AND PRINT Command
Table 10-5: SLEW AND PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (0Bh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Channel|
-----|-----------------------------------------------------------------------|
2 | Slew Value |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
-----|--- Transfer Length ---|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The SLEW AND PRINT command (Table 10-5) transfers the specified number of
bytes from the initiator to the target to be printed. This command is
provided for printer devices that do not support forms control information
embedded within the print data.
The transfer length specifies the length in bytes of data that shall be
transferred during the DATA OUT phase. A transfer length of zero indicates
that no data shall be transferred. This condition shall not be considered as
an error.
If the channel bit is zero, the slew value specifies the number of lines the
form shall be advanced before printing. A value of 255 indicates that the
form shall be advanced to the first line of the next form before printing. If
the channel bit is one, the slew value specifies the forms control channel
number to which the form shall be advanced prior to printing the data. If
implemented, the printer options page in the MODE SELECT command provides
additional control over the usage of the slew value field.
If the channel bit is one, and the channel option is not implemented, the
command shall be terminated with CHECK CONDITION status and the sense key
shall be set to ILLEGAL REQUEST.
10.2.5. STOP PRINT Command
Table 10-6: STOP PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (1Bh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Retain |
-----|-----------------------------------------------------------------------|
2 | Vendor Unique |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The STOP PRINT command (Table 10-6) requests the target to halt printing on
buffered devices in an orderly fashion.
A retain bit of zero requests that the target data buffer be discarded;
otherwise, the data not printed shall be retained. The data not printed may
be recovered using the RECOVER BUFFERED DATA command, if implemented by the
target. A subsequent SYNCHRONIZE BUFFER command, PRINT command or SLEW AND
PRINT command shall cause the remaining data not already printed and to be
printed followed by the data transferred by the subsequent command, if any.
The point at which printing is suspended by this command is vendor specific.
10.2.6. SYNCHRONIZE BUFFER Command
Table 10-7: SYNCHRONIZE BUFFER Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (10h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The SYNCHRONIZE BUFFER command (Table 10-7) provides a means for an
initiator to ensure that the data have been successfully printed prior to
releasing the peripheral device. This is useful for applications that wish to
handle any error or exception conditions (e.g., end-of-medium) prior to
termination of the application.
When all buffered data are actually printed the command shall be terminated
with a GOOD status. If it is not possible to finish printing all of the
buffered data (due to an error or exception condition on the peripheral
device), then this command shall be terminated with a CHECK CONDITION status
and the appropriate sense key.
The printer options page in the MODE SELECT command, if implemented,
provides additional control over termination sequences when using this
command.
10.3. Parameters for Printer Devices
10.3.1. Diagnostic Parameters
This section defines the descriptors and pages for diagnostic parameters
used with printer devices.
The diagnostic page codes for printer devices are defined in Table 10-8.
Table 10-8: Diagnostic Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
00h Supported Diagnostic Pages 7.3.1.1
01h-3Fh Reserved (for all device type pages)
40h-7Fh Reserved
80h-FFh Vendor-specific pages
==============================================================================
10.3.2. Log Parameters
This section defines the descriptors and pages for log parameters used with
printer devices.
The log page codes for printer devices are defined in Table 10-9.
Table 10-9: Log Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
01h Buffer Over-Run/Under-Run Page 7.3.2.1
07h Last n Error Events Page 7.3.2.3
06h Non-Medium Error Page 7.3.2.4
00h Supported Log Pages 7.3.2.5
02h - 05h Reserved
08h - 2Fh Reserved
3Fh Reserved
30h - 3Eh Vendor-specific pages
==============================================================================
10.3.3. Mode Parameters
This section defines the descriptors and pages for mode parameters used with
printer devices.
The mode parameter list, including the mode parameter header and mode block
descriptor are described in 7.3.3.
The medium-type code field is contained in the mode parameter header (see
Table 7-61 and 7-62). This field is reserved for printer devices.
The device specific parameter field is contained in the mode parameter
header (see Table 7-61 and 7-62). Table 10-10 defines the device specific
parameter used for printer devices.
Table 10-10: Printer Device Specific Parameter
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
==============================================================================
|Reserved| Buffered Mode | Reserved |
==============================================================================
When using the MODE SELECT command, a buffered mode of zero indicates that
the target shall not report a GOOD status on PRINT commands or SLEW AND PRINT
commands until the data are actually printed. A buffered mode of one
indicates that the target may report a GOOD status on PRINT commands or SLEW
AND PRINT commands as soon as the data have been transferred to the SCSI
device buffer. The data from one or more commands may be buffered prior to
printing. Buffered modes of 2h through 7h are reserved.
When using the MODE SENSE command, the buffered mode field returns the
current value of this parameter.
The density code field is contained in the mode parameter block descriptor
(see Table 7-63). This field is reserved for printer devices.
The mode page codes for printer devices are shown in Table 10-11.
Table 10-11: Mode Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
00h Vendor Specific (does not require page format)
0Ah Control Mode Page 7.3.3.1
02h Disconnect-Reconnect Page 7.3.3.2
03h Parallel Printer Interface Parameters 10.3.3.1
09h Peripheral Device Page 7.3.3.3
05h Printer Options 10.3.3.2
04h Serial Printer Interface Parameters 10.3.3.3
01h Reserved
06h - 08h Reserved
0Bh - 1Fh Reserved
20h - 3Eh Vendor Specific (page format required)
3Fh Returns all pages (valid only for the MODE SENSE command)
==============================================================================
10.3.3.1. Parallel Printer Interface Parameters Page
This page (Table 10-12) is intended to support printer devices which use the
industry-standard line printer interface.
Table 10-12: Parallel Printer Interface Parameters
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (03h) |
-----|-----------------------------------------------------------------------|
1 | Parameter Length (03h) |
-----|-----------------------------------------------------------------------|
2 | Parity Select | PIPC |Reserved| VCBP | VCBS | VES | Autofd |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
The parameters savable (PS) bit is only used with the MODE SENSE command.
This bit is reserved with the MODE SELECT command. A PS bit of one indicates
that the target is capable of saving the page in a non-volatile vendor-
specific location.
The parity select field specifies parity generation on the printer interface
and is defined as follows:
Code Parity Select
---- -------------------------
00b No parity generation
01b Even Parity
10b Odd Parity
11b Reserved
A paper instruction parity check (PIPC) bit of one indicates that the
printer interface "Paper Instruction" signal is included in parity generation
on the printer interface by the target. A PIPC bit of zero indicates that the
"Paper Instruction" signal is not included in parity generation on the printer
interface by the target.
IMPLEMENTORS NOTES:
(1) The format of the vertical forms unit (VFU) control byte is specified by
the VCBP, VCBS, and VES bits. The VFU control byte is not part of this
standard, however a discussion of it is included here for a better
understanding. This VFU control byte (see table, below) includes a control
bit (C) to select whether to slew over a number of lines or to skip to a
vertical forms unit (VFU) channel number. This bit may be located in two
different bit positions and may have either polarity.
(2) The number of lines to slew over may be coded as an unsigned four-bit
number (NNNN) or an unsigned six-bit number (EENNNN). The upper two bits of
the six-bit number (EE) may be positioned contiguously with the lower four
bits (NNNN) or they may be separated from the lower four bits by the control
bit (C). Furthermore, the upper two bits may or may not be supported.
(3) The VFU channel to select is specified by an unsigned four-bit number
(NNNN) in the VFU control byte.
(4) Pictorially, the control byte is as follows:
VFU Control Byte Description
7 6 5 4 3 2 1 0
--------------- ------------------------------------------
0 E E C N N N N Advance (EE)NNNN lines (C = line skip)
0 0 0 C N N N N Skip to VFU channel NNNN (C = VFU channel)
0 C E E N N N N Advance (EE)NNNN lines (C = line skip)
0 C 0 0 N N N N Skip to VFU channel NNNN (C = VFU channel)
Key: C is the VFU control bit.
A VFU control bit polarity (VCBP) bit of one indicates that the the VFU
control bit (C) is true for a VFU channel command and false for a line skip
command. A VCBP bit of zero indicates the opposite polarity.
A VFU control bit select (VCBS) bit of one indicates that the control bit
(C) is in bit position 6 and the EE bits are in bit positions 5 and 4. A VCBS
bit of zero indicates that the control bit (C) is in bit position 4 and the EE
bits are in bit positions 6 and 5.
A VFU extended skip (VES) bit of one indicates that the EE bits are
supported for line skip operations. A VES bit of zero indicates that the EE
bits are not supported.
For MODE SELECT an automatic line feed (Autofd) bit of one specifies that
the target assert the printer interface "Auto Line Feed" signal. An Autofd
bit of zero specifies that the target negate the printer interface "Auto Line
Feed" signal. For MODE SENSE the target shall return the current value of
this bit.
10.3.3.2. Printer Options Page
The printer options page (Table 10-13) supports control and reporting of
various target functions and features.
Table 10-13: Printer Options
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (05h) |
-----|-----------------------------------------------------------------------|
1 | Parameter Length (0Ah) |
-----|-----------------------------------------------------------------------|
2 | EVFU | Font Identification |
-----|-----------------------------------------------------------------------|
3 | Reserved | Slew Mode | Reserved | SCTE | AFC |
-----|-+---------------------------------------------------------------------|
4 | (MSB) |
-----|--- Maximum Line Length ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | EVFU Format Start Character |
-----|-----------------------------------------------------------------------|
7 | EVFU Format Stop Character |
-----|-+---------------------------------------------------------------------|
8 | Line Slew options | Form Slew Options |
-----|-----------------------------------------------------------------------|
9 | Data Termination Options | Reserved |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Reserved |
==============================================================================
The parameters savable (PS) bit is only used with the MODE SENSE command.
This bit is reserved with the MODE SELECT command. A PS bit of one indicates
that the target is capable of saving the page in a non-volatile vendor-
specific location.
An electronic vertical forms unit (EVFU) bit of one indicates that a tape or
electronic vertical forms unit is present in the printer device. An EVFU bit
of zero indicates that the electronic vertical forms unit should not be used
or that the unit is not present in the printer device.
For the MODE SELECT command, the font identification field specifies which
font is to be used. For the MODE SENSE command, this field identifies the
currently selected font. The font identification codes are defined as
follows:
Code Font Identification
--------- --------------------
00h Default Font
01h - 3Fh Reserved
40h - 7Fh Vendor specific Font
For the MODE SELECT command, the slew mode field controls the target's
behavior when a SLEW AND PRINT command is received with a channel bit of zero
(see 10.2.4). For the MODE SENSE command, this field reports the current slew
mode. This slew mode is defined as follows:
Code Slew Mode
---- ----------------------------------------------------------------------
00b SLEW AND PRINT commands with a channel bit of zero are supported
without any required setup.
01b SLEW AND PRINT commands with a channel bit of zero are only accepted
after the initiator issues a FORMAT command with a format type of "set
form" (to initialize the electronic vertical forms unit).
10b SLEW AND PRINT commands with a channel bit of zero are always
accepted. The target shall use the electronic vertical forms unit if
it has previously been initialized or it shall initialize the
electronic vertical forms unit for line skipping by sending the EVFU
start format character immediately followed by the EVFU stop format
character (both are defined below) prior to executing the SLEW AND
PRINT command.
11b Reserved
For the MODE SELECT command, a step count truncate enable (SCTE) bit of one
indicates that the target shall assume the printer truncates slew values in
SLEW AND PRINT commands so that the data is printed on the first line of the
next form. A SCTE bit of zero indicates that the target shall assume the
printer continues to slew over forms boundaries in SLEW AND PRINT commands if
the slew value exceeds the number of remaining lines on the current form. The
target shall return the current value of this field in the MODE SENSE data.
An ASCII forms control (AFC) bit of one indicates that the printer supports
ASCII forms control characters. An AFC bit of zero indicates that the printer
does not support ASCII forms control characters.
The maximum line length field specifies the maximum transfer length (maximum
number of bytes per line) to be accepted in the SLEW AND PRINT command. A
value of 0000h in MODE SELECT specifies that the target shall use its default
value. In any case, the target shall report its actual value in the MODE
SENSE data (not 0000h).
The EVFU format start character field specifies the character code to be
used by the target to start the initialization of the electronic vertical
forms unit if slew mode option 10b is selected.
The EVFU format stop character field specifies the character code to be used
by the target to stop the initialization of the electronic vertical forms unit
if slew mode option 10b is selected.
The line slew options field specifies the implementation of the line slew
(using ASCII forms control characters) in the SLEW AND PRINT command. Code
values in this field are defined as follows:
Code Line Slew Option
----- ----------------------------------------------------------------------
0h Not implemented. (SLEW AND PRINT commands cause CHECK CONDITION
status with ILLEGAL REQUEST sense key.)
1h The target shall insert an ASCII carriage return character (0Dh) for
each line to slew over.
2h The target shall insert an ASCII line feed character (0Ah) for each
line to slew over.
3h The target shall insert an ASCII carriage return character (0Dh) and
line feed character (0Ah) for each line to slew over.
4h-7h Reserved
8h-Fh Vendor Unique
The form slew options field specifies the implementation of form slewing in
the SLEW AND PRINT command. Code values in this field are defined as follows:
Code Form Slew Option
----- ----------------------------------------------------------------------
0h Not implemented. (SLEW AND PRINT commands cause CHECK CONDITION
status with ILLEGAL REQUEST sense key.)
1h The target shall insert an ASCII form feed character (0Ch) to move to
the beginning of the next form.
2h The target shall insert an ASCII carriage return character (0Dh) and
form feed character (0Ch) to move to the beginning of the next form.
3h-7h Reserved
8h-Fh Vendor Unique
The data termination options field specifies the termination sequence to be
issued to the printer device when a SYNCHRONIZE BUFFER command is received.
Code values for this field are defined as follows:
Code Data Termination Option
----- -----------------------
0h Selects the target default implementation (MODE SELECT).
1h No termination sequence. (The target sends any remaining data in its
buffer to the printer device with no termination sequence.)
2h The target shall print any buffered data followed by an ASCII carriage
return character (0Dh).
3h The target shall print any buffered data followed by an ASCII line
feed character (0Ah).
4h The target shall print any buffered data followed by an ASCII carriage
return, line feed character sequence (0Dh, 0Ah).
5h The target shall send any buffered data followed by an ASCII form feed
character (0Ch).
6h The target shall print any buffered data followed by an ASCII carriage
return, form feed character sequence (0Dh, 0Ch).
7h The target shall issue a zero line slew command to the printer device.
8h-Bh Reserved
Ch-Fh Vendor Unique
10.3.3.3. Serial Printer Interface Parameters Page
This page (Table 10-14) is intended to support printer devices which use the
industry-standard serial interface usually referred to as EIA RS-232C.
Table 10-14: Serial Printer Interface Parameters
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (04h) |
-----|-----------------------------------------------------------------------|
1 | Parameter Length (06h) |
-----|-----------------------------------------------------------------------|
2 | Reserved | Stop Bit Length |
-----|-----------------------------------------------------------------------|
3 | Parity Selection |Reserved| Bits per Character |
-----|-+---------------------------------------------------------------------|
4 | RTS | CTS | Reserved | Pacing Protocol |
-----|-----------------------------------------------------------------------|
5 | (MSB) |
-----|--- ---|
6 | Baud Rate |
-----|--- ---|
7 | (LSB) |
==============================================================================
The parameters savable (PS) bit is only used with the MODE SENSE command.
This bit is reserved with the MODE SELECT command. A PS bit of one indicates
that the target is capable of saving the page in a non-volatile vendor-
specific location.
The stop bit length field specifies the length of the stop bit(s) in units
of 1/16 bit. The target may round this field as described in 6.5.4. A stop
bit length of zero in the MODE SELECT command indicates that the target shall
use its default value.
The parity selection field specifies parity generation and checking as
defined in the following table:
Code Parity Selection
---- ----------------
000b None
001b Mark
010b Space
011b Odd
100b Even
101b Reserved
110b Reserved
111b Reserved
The bits per character field specifies the number of bits in each character.
A value of zero in the MODE SELECT command indicates that the target shall use
its default character size.
For the MODE SELECT command, a request to send (RTS) bit of one specifies
that the target shall insure the "Request to Send" (RTS) signal in the serial
interface follows the line state of the "Data Terminal Ready" (DTR) signal in
the serial interface. A RTS bit of zero specifies that the target shall set
the "Request to Send" (RTS) signal to "high" whenever the target power is on.
For the MODE SENSE command, the target shall report the current value of this
field.
For the MODE SELECT command, a clear to send (CTS) bit of one specifies that
the target shall delay data transmission to the printer device until the
printer device asserts the "Clear to Send" (CTS) signal in the serial
interface. A CTS bit of zero indicates that the target shall ignore the
"Clear to Send" signal. For the MODE SENSE command, the target shall report
the current value of this field.
The code values for the pacing protocol field are defined as follows:
Code Pacing Protocol
---- ---------------
0h None
1h XON/XOFF
2h ETX/ACK
3h DTR
4h-7h Reserved
8h-Fh Vendor specific
The baud rate field specifies the baud rate in bits per second. The target
may round this value as described in 6.5.4. A baud rate of zero in the MODE
SELECT command specifies that the target shall use its default baud rate.
(This page is intentionally blank.)
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