Ioctl Requests termiox(7I)
NAME
termiox - extended general terminal interface
DESCRIPTION
The extended general terminal interface supplements the termio(7I) general terminal interface by adding support for asynchronous hardware flow control, isochronous flow control and clock modes, and local implementations of additional asynchronous features. Some systems may not support all of these capabilities because of either hardware or software limitations. Other systems may not permit certain functions to be disabled. In these cases the appropriate bits will beignored. See
which capabilities are supported. Hardware Flow Control Modes Hardware flow control supplements the termio(7I) IXON,for your system to find out IXOFF, and IXANY character flow control. Character flow con-
trol occurs when one device controls the data transfer of another device by the insertion of control characters in the data stream between devices. Hardware flow control occurs when one device controls the data transfer of another device using electrical control signals on wires (circuits) of the asynchronous interface. Isochronous hardware flow control occurs when one device controls the data transfer of another device by asserting or removing the transmit clock signals of that device. Character flow control and hardware flow control may be simultaneously set. In asynchronous, full duplex applications, the use of theElectronic Industries Association's EIA-232-D Request To
Send (RTS) and Clear To Send (CTS) circuits is the pre-
ferred method of hardware flow control. An interface to other hardware flow control methods is included to provide a standard interface to these existing methods.The EIA-232-D standard specified only unidirectional
hardware flow control - the Data Circuit-terminating Equip-
ment or Data Communications Equipment (DCE) indicates to the Data Terminal Equipment (DTE) to stop transmitting data.The termiox interface allows both unidirectional and
bidirectional hardware flow control; when bidirectional flow control is enabled, either the DCE or DTE can indicate to each other to stop transmitting data across the interface. Note: It is assumed that the asynchronous port is configured as a DTE. If the connected device is also a DTE and not aDCE, then DTE to DTE (for example, terminal or printer con-
nected to computer) hardware flow control is possible by using a null modem to interconnect the appropriate data and control circuits.SunOS 5.11 Last change: 3 Jul 1990 1
Ioctl Requests termiox(7I)
Clock Modes Isochronous communication is a variation of asynchronous communication whereby two communicating devices may providetransmit and/or receive clock signals to one another. Incom-
ing clock signals can be taken from the baud rate generator on the local isochronous port controller, from CCITT V.24circuit 114, Transmitter Signal Element Timing - DCE source
(EIA-232-D pin 15), or from CCITT V.24 circuit 115,
Receiver Signal Element Timing - DCE source (EIA-232-D pin
17). Outgoing clock signals can be sent on CCITT V.24 cir-
cuit 113, Transmitter Signal Element Timing - DTE source
(EIA-232-D pin 24), on CCITT V.24 circuit 128, Receiver
Signal Element Timing - DTE source (no EIA-232-D pin), or
not sent at all.In terms of clock modes, traditional asynchronous communica-
tion is implemented simply by using the local baud rate gen-
erator as the incoming transmit and receive clock source and not outputting any clock signals. Terminal ParametersThe parameters that control the behavior of devices provid-
ing the termiox interface are specified by the termiox
structure defined in the
ioctl(2) system calls that fetch or change these parameters use this structure:header. Several #define NFF 5
struct termiox {
unsigned short x_hflag; /* hardware flow control modes */
unsigned short x_cflag; /* clock modes */
unsigned short x_rflag[NFF]; /* reserved modes */
unsigned short x_sflag; /* spare local modes */
};The x_hflag field describes hardware flow control modes:
RTSXOFF 0000001 Enable RTS hardware flow control on input. CTSXON 0000002 Enable CTS hardware flow control on output. DTRXOFF 0000004 Enable DTR hardware flow control on input. CDXON 0000010 Enable CD hardware flow control on output.SunOS 5.11 Last change: 3 Jul 1990 2
Ioctl Requests termiox(7I)
ISXOFF 0000020 Enable isochronous hardware flow control on inputThe EIA-232-D DTR and CD circuits are used to establish a
connection between two systems. The RTS circuit is also used to establish a connection with a modem. Thus, both DTR and RTS are activated when an asynchronous port is opened. If DTR is used for hardware flow control, then RTS must be used for connectivity. If CD is used for hardware flow control, then CTS must be used for connectivity. Thus, RTS and DTR(or CTS and CD) cannot both be used for hardware flow con-
trol at the same time. Other mutual exclusions may apply, such as the simultaneous setting of the termio(7I) HUPCL andthe termiox DTRXOFF bits, which use the DTE ready line for
different functions. Variations of different hardware flow control methods may be selected by setting the the appropriate bits. For example,bidirectional RTS/CTS flow control is selected by setting
both the RTSXOFF and CTSXON bits and bidirectional DTR/CTS flow control is selected by setting both the DTRXOFF and CTSXON. Modem control or unidirectional CTS hardware flow control is selected by setting only the CTSXON bit.
As previously mentioned, it is assumed that the local asyn-
chronous port (for example, computer) is configured as a DTE. If the connected device (for example, printer) is also a DTE, it is assumed that the device is connected to the computer's asynchronous port using a null modem thatswaps control circuits (typically RTS and CTS). The con-
nected DTE drives RTS and the null modem swaps RTS and CTS so that the remote RTS is received as CTS by the local DTE. In the case that CTSXON is set for hardware flow control, printer's lowering of its RTS would cause CTS seen by the computer to be lowered. Output to the printer is suspended until the printer's raising of its RTS, which would cause CTS seen by the computer to be raised. If RTSXOFF is set, the Request To Send (RTS) circuit (line) will be raised, and if the asynchronous port needs to have its input stopped, it will lower the Request To Send (RTS) line. If the RTS line is lowered, it is assumed that the connected device will stop its output until RTS is raised. If CTSXON is set, output will occur only if the Clear To Send (CTS) circuit (line) is raised by the connected device.SunOS 5.11 Last change: 3 Jul 1990 3
Ioctl Requests termiox(7I)
If the CTS line is lowered by the connected device, output is suspended until CTS is raised. If DTRXOFF is set, the DTE Ready (DTR) circuit (line) will be raised, and if the asynchronous port needs to have its input stopped, it will lower the DTE Ready (DTR) line. If the DTR line is lowered, it is assumed that the connected device will stop its output until DTR is raised. If CDXON is set, output will occur only if the Received LineSignal Detector (CD) circuit (line) is raised by the con-
nected device. If the CD line is lowered by the connected device, output is suspended until CD is raised. If ISXOFF is set, and if the isochronous port needs to have its input stopped, it will stop the outgoing clock signal. It is assumed that the connected device is using this clock signal to create its output. Transit and receive clocksources are programmed using the x_cflag fields. If the port
is not programmed for external clock generation, ISXOFF is ignored. Output isochronous flow control is supported byappropriate clock source programming using the x_cflag field
and enabled at the remote connected device.The x_cflag field specifies the system treatment of clock
modes. XMTCLK 0000007 Transmit clock source:XCIBRG 0000000 Get transmit clock from inter-
nal baud rate generator. XCTSET 0000001 Get transmit clock fromtransmitter signal element tim-
ing (DCE source) lead, CCITTV.24 circuit 114, EIA-232-D pin
15. XCRSET 0000002 Get transmit clock from receiver signal element timing (DCE source) lead, CCITT V.24circuit 115, EIA-232-D pin 17.
RCVCLK 0000070 Receive clock source: RCIBRG 0000000 Get receive clock from internal baud rate generator.SunOS 5.11 Last change: 3 Jul 1990 4
Ioctl Requests termiox(7I)
RCTSET 0000010 Get receive clock fromtransmitter signal element tim-
ing (DCE source) lead, CCITTV.24 circuit 114, EIA-232-D pin
15. RCRSET 0000020 Get receive clock from receiver signal element timing (DCEsource) lead, CCITT V.24 cir-
cuit 115, EIA-232-D pin 17.
TSETCLK 0000700 Transmitter signal element tim-
ing (DTE source) lead, CCITTV.24 circuit 113, EIA-232-D pin
24, clock source: TSETCOFF 0000000 TSET clock not provided.TSETCRBRG 0000100 Output receive baud rate gen-
erator on circuit 113.TSETCTBRG 0000200 Output transmit baud rate gen-
erator on circuit 113TSETCTSET 0000300 Output transmitter signal ele-
ment timing (DCE source) on circuit 113. TSETCRSET 0000400 Output receiver signal element timing (DCE source) on circuit 113. RSETCLK 0007000 Receiver signal element timing (DTE source) lead, CCITT V.24circuit 128, no EIA-232-D pin,
clock source: RSETCOFF 0000000 RSET clock not provided.RSETCRBRG 0001000 Output receive baud rate gen-
erator on circuit 128.RSETCTBRG 0002000 Output transmit baud rate gen-
erator on circuit 128.RSETCTSET 0003000 Output transmitter signal ele-
ment timing (DCE source) on circuit 128. RSETCRSET 0004000 Output receiver signal element timing (DCE) on circuit 128. If the XMTCLK field has a value of XCIBRG the transmit clock is taken from the hardware internal baud rate generator, as in normal asynchronous transmission. If XMTCLK = XCTSET the transmit clock is taken from the Transmitter Signal Element Timing (DCE source) circuit. If XMTCLK = XCRSET the transmit clock is taken from the Receiver Signal Element Timing (DCE source) circuit. If the RCVCLK field has a value of RCIBRG the receive clock is taken from the hardware Internal Baud Rate Generator, asSunOS 5.11 Last change: 3 Jul 1990 5
Ioctl Requests termiox(7I)
in normal asynchronous transmission. If RCVCLK = RCTSET the receive clock is taken from the Transmitter Signal Element Timing (DCE source) circuit. If RCVCLK = RCRSET the receive clock is taken from the Receiver Signal Element Timing (DCE source) circuit. If the TSETCLK field has a value of TSETCOFF the Transmitter Signal Element Timing (DTE source) circuit is not driven. If TSETCLK = TSETCRBRG the Transmitter Signal Element Timing(DTE source) circuit is driven by the Receive Baud Rate Gen-
erator. If TSETCLK = TSETCTBRG the Transmitter Signal Ele-
ment Timing (DTE source) circuit is driven by the Transmit Baud Rate Generator. If TSETCLK = TSETCTSET the Transmitter Signal Element Timing (DTE source) circuit is driven by the Transmitter Signal Element Timing (DCE source). If TSETCLK = TSETCRBRG the Transmitter Signal Element Timing (DTE source) circuit is driven by the Receiver Signal Element Timing (DCE source). If the RSETCLK field has a value of RSETCOFF the Receiver Signal Element Timing (DTE source) circuit is not driven. If RSETCLK = RSETCRBRG the Receiver Signal Element Timing (DTEsource) circuit is driven by the Receive Baud Rate Genera-
tor. If RSETCLK = RSETCTBRG the Receiver Signal Element Timing (DTE source) circuit is driven by the Transmit Baud Rate Generator. If RSETCLK = RSETCTSET the Receiver Signal Element Timing (DTE source) circuit is driven by the Transmitter Signal Element Timing (DCE source). If RSETCLK = RSETCRBRG the Receiver Signal Element Timing (DTE source) circuit is driven by the Receiver Signal Element Timing (DCE source).The x_rflag is reserved for future interface definitions and
should not be used by any implementations. The x_sflag may
be used by local implementations wishing to customize theirterminal interface using the termiox ioctl system calls.
IOCTLS The ioctl(2) system calls have the form:ioctl (fildes, command, arg) struct termiox * arg;
The commands using this form are:TCGETX The argument is a pointer to a termiox structure.
The current terminal parameters are fetched and stored into that structure.SunOS 5.11 Last change: 3 Jul 1990 6
Ioctl Requests termiox(7I)
TCSETX The argument is a pointer to a termiox structure.
The current terminal parameters are set from the values stored in that structure. The change is immediate.TCSETXW The argument is a pointer to a termiox structure.
The current terminal parameters are set from the values stored in that structure. The change occurs after all characters queued for output have been transmitted. This form should be used when changing parameters that will affect output.TCSETXF The argument is a pointer to a termiox structure.
The current terminal parameters are set from the values stored in that structure. The change occurs after all characters queued for output have been transmitted; all characters queued for input are discarded and then the change occurs. FILES /dev/*SEE ALSO
stty(1), ioctl(2), termio(7I) NOTESThe termiox(7I) system call is provided for compatibility
with previous releases and its use is discouraged. Instead, the termio(7I) system call is recommended. See termio(7I) for usage information.SunOS 5.11 Last change: 3 Jul 1990 7