isdnio(7I) Ioctl Requests isdnio(7I)NAMEisdnio - ISDN interfaces
SYNOPSIS
#include <sun/audioio.h>
#include <sun/isdnio.h>
int ioctl(int fd, int command, /* arg */ ...);
DESCRIPTION
ISDN ioctl commands are a subset of ioctl(2) commands that perform a
variety of control functions on Integrated Services Digital Network
(ISDN) STREAMS devices. The arguments command and arg are passed to the
file designated by fd and are interpreted by the ISDN device driver.
fd is an open file descriptor that refers to a stream. command deter‐
mines the control function to be performed as described in the IOCTLS
section of this document. arg represents additional information that is
needed by command. The type of arg depends upon the command, but gener‐
ally it is an integer or a pointer to a command-specific data struc‐
ture.
Since these ISDN commands are a subset of ioctl and streamio(7I), they
are subject to errors as described in those interface descriptions.
This set of generic ISDN ioctl commands is meant to control various
types of ISDN STREAMS device drivers. The following paragraphs give
some background on various types of ISDN hardware interfaces and data
formats, and other device characteristics.
Controllers, Interfaces, and Channels
This manual page discusses operations on, and facilities provided by
ISDN controllers, interfaces and channels. A controller is usually a
hardware peripheral device that provides one or more ISDN interfaces
and zero or more auxiliary interfaces. In this context, the term inter‐
face is synonymous with the term "port". Each interface can provide one
or more channels.
Time Division Multiplexed Serial Interfaces
ISDN BRI-TE, BRI-NT, and PRI interfaces are all examples of Time Divi‐
sion Multiplexed Serial Interfaces. As an example, a Basic Rate ISDN
(BRI) Terminal Equipment (TE) interface provides one D-channel and two
B-channels on the same set of signal wires. The BRI interface, at the S
reference point, operates at a bit rate of 192,000 bits per second. The
bits are encoded using a pseudoternary coding system that encodes a
logic one as zero volts, and a logic zero as a positive or negative
voltage. Encoding rules state that adjacent logic zeros must be encoded
with opposite voltages. Violations of this rule are used to indicate
framing information such that there are 4000 frames per second, each
containing 48 bits. These 48 bits are divided into channels. Not
including framing and synchronization bits, the frame is divided into 8
bits for the B1-channel, 1 bit for the D-channel, 8 bits for B2, 1 bit
for D, 8 bits for B1, 1 bit for D, and 8 bits for B2. This results in a
64,000 bps B1-channel, a 64,000 bps B2-channel, and a 16,000 bps D-
channel, all on the same serial interface.
Basic Rate ISDN
A Basic Rate ISDN (BRI) interface consists of a 16000 bit per second
Delta Channel (D-channel) for signaling and X.25 packet transmission,
and two 64000 bit per second Bearer Channels (B-channels) for transmis‐
sion of voice or data.
The CCITT recommendations on ISDN Basic Rate interfaces, I.430, iden‐
tify several "reference points" for standardization. From
(Stallings89): Reference point T (terminal) corresponds to a minimal
ISDN network termination at the customer's premises. It separates the
network provider's equipment from the user's equipment. Reference point
S (system) corresponds to the interface of individual ISDN terminals.
It separates user terminal equipment from network-related communica‐
tions functions. Reference point R (rate) provides a non-ISDN interface
between user equipment that is not ISDN-compatible and adaptor equip‐
ment. ... The final reference point ... is reference point U (user).
This interface describes the full-duplex data signal on the subscriber
line.
Some older technology components of some ISDN networks occasionally
steal the low order bit of an ISDN B-channel octet in order to transmit
in-band signaling information between switches or other components of
the network. Even when out-of-band signaling has been implemented in
these networks, and the in-band signaling is no longer needed, the bit-
robbing mechanism may still be present. This bit robbing behavior does
not appreciably affect a voice call, but it will limit the usable band‐
width of a data call to 56000 bits per second instead of 64000 bits per
second. These older network components only seem to exist in the United
States of America, Canada and Japan. ISDN B-channel data calls that
have one end point in the United States, Canada or Japan may be limited
to 56000 bps usable bandwidth instead of the normal 64000 bps. Some‐
times the ISDN service provider may be able to supply 56kbps for some
calls and 64kbps for other calls. On an international call, the local
ISDN service provider may advertise the call as 64kbps even though only
56kbps are reliably delivered because of bit-robbing in the foreign
ISDN that is not reported to the local switch.
A Basic Rate Interface implements either a Terminal Equipment (TE)
interface or a Network Termination (NT) interface. TE's can be ISDN
telephones, a Group 4 fax, or other ISDN terminal equipment. A TE con‐
nects to an NT in order to gain access to a public or private ISDN net‐
work. A private ISDN network, such as provided by a Private Branch
Exchange (PBX), usually provides access to the public network.
If multi-point configurations are allowed by an NT, it may be possible
to connect up to eight TE's to a single NT interface. All of the TE's
in a multipoint configuration share the same D and B-channels. Con‐
tention for B-Channels by multiple TEs is resolved by the ISDN switch
(NT) through signaling protocols on the D-channel.
Contention for access to the D-channel is managed by a collision detec‐
tion and priority mechanism. D-channel call control messages have
higher priority than other packets. This media access function is man‐
aged at the physical layer.
A BRI-TE interface may implement a "Q-channel", the Q-channel is a slow
speed, 800 bps, data path from a TE to an NT. Although the structure of
the Q-channel is defined in the I.430 specification, the use of the Q-
channel is for further study.
A BRI-NT interface may implement an "S-channel", the S-channel is a
slow speed, 4000 bps, data path from a NT to an TE. The use of the S-
channel is for further study.
Primary Rate ISDN
Primary Rate ISDN (PRI) interfaces are either 1.544Mbps (T1 rate) or
2.048Mbps (E1 rate) and are typically organized as 23 B-channels and
one D-Channel (23B+D) for T1 rates, and 30 B-Channels and one D-Channel
(30B+D) for E1 rates. The D-channels on a PRI interface operate at
64000 bits per second. T1 rate PRI interface is the standard in the
United States, Canada and Japan while E1 rate PRI interface is the
standard in European countries. Some E1 rate PRI interface implementa‐
tions allow access to channel zero which is used for framing.
Channel Types
ISDN channels fall into several categories; D-channels, bearer chan‐
nels, and management pseudo channels. Each channel has a corresponding
device name somewhere under the directory /dev/isdn/ as documented in
the appropriate hardware specific manual page.
D-channels
There is at most one D-channel per ISDN interface. The D-channel
carries signaling information for the management of ISDN calls and
can also carry X.25 packet data. In the case of a PRI interface,
there may actually be no D-channel if Non-Facility Associated Sig‐
naling is used. D-channels carry data packets that are framed and
checked for transmission errors according to the LAP-D protocol.
LAP-D uses framing and error checking identical to the High Speed
Data Link (HDLC) protocol.
B-channels
BRI interfaces have two B-channels, B1 and B2. On a BRI interface,
the only other type of channel is an H-channel which is a concate‐
nation of the B1 and B2 channels. An H-channel is accessed by open‐
ing the "base" channel, B1 in this case, and using the
ISDN_SET_FORMAT ioctl to change the configuration of the B-channel
from 8-bit, 8 kHz to 16-bit, 8kHz.
On a primary rate interface, B channels are numbered from 0 to 31
in Europe and 1 to 23 in the United States, Canada and Japan.
H-Channels
A BRI or PRI interface can offer multiple B-channels concatenated
into a single, higher bandwidth channel. These concatenated B-chan‐
nels are referred to as an "H-channels" on a BRI interface. The
PRI interface version of an H-channel is referred to as an Hn-chan‐
nels where n is a number indicating how the B-channels have been
aggregated into a single channel.
· A PRI interface H0 channel is 384 kbps allowing 3H0+D on a T1
rate PRI interface and 4H0+D channels on an E1 rate PRI inter‐
face.
· A T1 PRI interface H11 channel is 1536 kbps (24~64000bps).
This will consume the channel normally reserved for the D-
channel, so signaling must be done with Non-Facility Associ‐
ated Signaling (NFAS) from another PRI interface.
· An E1 PRI interface H12 channel is 1920 kbps (30~64000bps). An
H12-channel leaves room for the framing-channel as well as the
D-channel.
Auxiliary channels
Auxiliary channels are non-ISDN hardware interfaces that are
closely tied to the ISDN interfaces. An example would be a video or
audio coder/decoder (codec). The existence of an auxiliary channel
usually implies that one or more B-channels can be "connected" to
an auxiliary interface in hardware.
Management pseudo-channels
A management pseudo-channel is used for the management of a con‐
troller, interface, or hardware channel. Management channels allow
for out-of-band control of hardware interfaces and for out-of-band
notification of status changes. There is at least one management
device per hardware interface.
There are three different types of management channels implemented
by ISDN hardware drivers:
· A controller management device handles all ioctls that simul‐
taneously affect hardware channels on different interfaces.
Examples include resetting a controller, mu-code (as in the
Greek letter mu) downloading of a controller, or the connec‐
tion of an ISDN B-channel to an auxiliary channel that repre‐
sents an audio coder/decoder (codec). The latter case would be
accomplished using the ISDN_SET_CHANNEL ioctl.
· An interface management device handles all ioctls that affect
multiple channels on the same interface. Messages associated
with the activation and deactivation of an interface arrive on
the management device associated with the D channel of an ISDN
interface.
· Auxiliary interfaces may also have management devices. See the
hardware specific man pages for operations on auxiliary
devices.
Trace pseudo-channels
A device driver may choose to implement a trace device for a data
or management channel. Trace channels receive a special M_PROTO
header with the original channel's original M_PROTO or M_DATA mes‐
sage appended to the special header. The header is described by:
typedef struct {
uint_t seq; /* Sequence number */
int type; /* device dependent */
struct timeval timestamp;
char _f[8]; /* filler */
} audtrace_hdr_t;
ISDN Channel types
The isdn_chan_t type enumerates the channels available on ISDN inter‐
faces. If a particular controller implements any auxiliary channels
then those auxiliary channels will be described in a controller spe‐
cific manual page. The defined channels are described by the
isdn_chan_t type as shown below:
/* ISDN channels */
typedef enum {
ISDN_CHAN_NONE = 0x0, /* No channel given */
ISDN_CHAN_SELF, /* The channel performing the ioctl */
ISDN_CHAN_HOST, /* Unix STREAM */
ISDN_CHAN_CTRL_MGT, /* Controller management */
/* TE channel defines */
ISDN_CHAN_TE_MGT, /* Receives activation/deactivation */
ISDN_CHAN_TE_D_TRACE, /* Trace device for protocol analysis apps */
ISDN_CHAN_TE_D,
ISDN_CHAN_TE_B1,
ISDN_CHAN_TE_B2,
/* NT channel defines */
ISDN_CHAN_NT_MGT, /* Receives activation/deactivation */
ISDN_CHAN_NT_D_TRACE, /* Trace device for protocol analysis apps */
ISDN_CHAN_NT_D,
ISDN_CHAN_NT_B1,
ISDN_CHAN_NT_B2,
/* Primary rate ISDN */
ISDN_CHAN_PRI_MGT,
ISDN_CHAN_PRI_D,
ISDN_CHAN_PRI_B0, ISDN_CHAN_PRI_B1,
ISDN_CHAN_PRI_B2, ISDN_CHAN_PRI_B3,
ISDN_CHAN_PRI_B4, ISDN_CHAN_PRI_B5,
ISDN_CHAN_PRI_B6, ISDN_CHAN_PRI_B7,
ISDN_CHAN_PRI_B8, ISDN_CHAN_PRI_B9,
ISDN_CHAN_PRI_B10, ISDN_CHAN_PRI_B11,
ISDN_CHAN_PRI_B12, ISDN_CHAN_PRI_B13,
ISDN_CHAN_PRI_B14, ISDN_CHAN_PRI_B15,
ISDN_CHAN_PRI_B16, ISDN_CHAN_PRI_B17,
ISDN_CHAN_PRI_B18, ISDN_CHAN_PRI_B19,
ISDN_CHAN_PRI_B20, ISDN_CHAN_PRI_B21,
ISDN_CHAN_PRI_B22, ISDN_CHAN_PRI_B23,
ISDN_CHAN_PRI_B24, ISDN_CHAN_PRI_B25,
ISDN_CHAN_PRI_B26, ISDN_CHAN_PRI_B27,
ISDN_CHAN_PRI_B28, ISDN_CHAN_PRI_B29,
ISDN_CHAN_PRI_B30, ISDN_CHAN_PRI_B31,
/* Auxiliary channel defines */
ISDN_CHAN_AUX0, ISDN_CHAN_AUX1, ISDN_CHAN_AUX2, ISDN_CHAN_AUX3,
ISDN_CHAN_AUX4, ISDN_CHAN_AUX5, ISDN_CHAN_AUX6, ISDN_CHAN_AUX7
} isdn_chan_t;
ISDN Interface types
The isdn_interface_t type enumerates the interfaces available on ISDN
controllers. The defined interfaces are described by the isdn_inter‐
face_t type as shown below:
/* ISDN interfaces */
typedef enum {
ISDN_TYPE_UNKNOWN = -1, /* Not known or applicable */
ISDN_TYPE_SELF = 0, /*
* For queries, application may
* put this value into "type" to
* query the state of the file
* descriptor used in an ioctl.
*/
ISDN_TYPE_OTHER, /* Not an ISDN interface */
ISDN_TYPE_TE,
ISDN_TYPE_NT,
ISDN_TYPE_PRI,
} isdn_interface_t;
Activation and Deactivation of ISDN Interfaces
The management device associated with an ISDN D-channel is used to
request activation, deactivation and receive information about the
activation state of the interface. See the descriptions of the
ISDN_PH_ACTIVATE_REQ and ISDN_MPH_DEACTIVATE_REQ ioctls. Changes in the
activation state of an interface are communicated to the D-channel
application through M_PROTO messages sent up-stream on the management
device associated with the D-channel. If the D-channel protocol stack
is implemented as a user process, the user process can retrieve the
M_PROTO messages using the getmsg(2) system call.
These M_PROTO messages have the following format:
typedef struct isdn_message {
unsigned int magic; /* set to ISDN_PROTO_MAGIC */
isdn_interface_t type; /* Interface type */
isdn_message_type_t message; /* CCITT or vendor Primitive */
unsigned int vendor[5]; /* Vendor specific content */
} isdn_message_t;
typedef enum isdn_message_type {
ISDN_VPH_VENDOR = 0, /* Vendor specific messages */
ISDN_PH_AI, /* Physical: Activation Ind */
ISDN_PH_DI, /* Physical: Deactivation Ind */
ISDN_MPH_AI, /* Management: Activation Ind */
ISDN_MPH_DI, /* Management: Deactivation Ind */
ISDN_MPH_EI1, /* Management: Error 1 Indication */
ISDN_MPH_EI2, /* Management: Error 2 Indication */
ISDN_MPH_II_C, /* Management: Info Ind, connection */
ISDN_MPH_II_D /* Management: Info Ind, disconn. */
} isdn_message_type_t;
IOCTLS
STREAMS IOCTLS
All of the streamio(7I) ioctl commands may be issued for a device con‐
forming to the the isdnio interface.
ISDN interfaces that allow access to audio data should implement a rea‐
sonable subset of the audio(7I) interface.
ISDN ioctls
ISDN_PH_ACTIVATE_REQ
Request ISDN physical layer activation. This command is valid for
both TE and NT interfaces. fd must be a D-channel file descriptor.
arg is ignored.
TE activation will occur without use of the ISDN_PH_ACTIVATE_REQ
ioctl if the device corresponding to the TE D-channel is open,
"on", and the ISDN switch is requesting activation.
ISDN_MPH_DEACTIVATE_REQ
fd must be an NT D-channel file descriptor. arg is ignored.
This command requests ISDN physical layer de-activation. This is
not valid for TE interfaces. A TE interace may be turned off by use
of the ISDN_PARAM_POWER command or by close(2) on the associated
fd.
ISDN_ACTIVATION_STATUS
fd is the file descriptor for a D-channel, the management device
associated with an ISDN interface, or the management device associ‐
ated with the controller. arg is a pointer to an isdn_activa‐
tion_status_t structure. Although it is possible for applications
to determine the current activation state with this ioctl, a D-
channel protocol stack should instead process messages from the
management pseudo channel associated with the D-channel.
typedef struct isdn_activation_status {
isdn_interface_t type;
enum isdn_activation_state activation;
} isdn_activation_status_t;
typedef enum isdn_activation_state {
ISDN_OFF = 0, /* Interface is powered down */
ISDN_UNPLUGGED, /* Power but no-physical connection */
ISDN_DEACTIVATED_REQ, /* Pending Deactivation, NT Only */
ISDN_DEACTIVATED, /* Activation is permitted */
ISDN_ACTIVATE_REQ, /* Attempting to activate */
ISDN_ACTIVATED, /* Interface is activated */
} isdn_activation_state_t;
The type field should be set to ISDN_TYPE_SELF. The device specific
interface type will be returned in the type field.
The isdn_activation_status_t structure contains the interface type
and the current activation state. type is the interface type and
should be set by the caller to ISDN_TYPE_SELF.
ISDN_INTERFACE_STATUS
The ISDN_INTERFACE_STATUS ioctl retrieves the status and statistics
of an ISDN interface. The requesting channel must own the inter‐
face whose status is being requested or the ioctl will fail. fd is
the file descriptor for an ISDN interface management device. arg is
a pointer to a struct isdn_interface_info. If the interface field
is set to ISDN_TYPE_SELF, it will be changed in the returned struc‐
ture to reflect the proper device-specific interface of the
requesting fd.
typedef struct isdn_interface_info {
isdn_interface_t interface;
enum isdn_activation_state activation;
unsigned int ph_ai; /* Physical: Activation Ind */
unsigned int ph_di; /* Physical: Deactivation Ind */
unsigned int mph_ai; /* Management: Activation Ind */
unsigned int mph_di; /* Management: Deactivation Ind */
unsigned int mph_ei1; /* Management: Error 1 Indication */
unsigned int mph_ei2; /* Management: Error 2 Indication */
unsigned int mph_ii_c; /* Management: Info Ind, connection */
unsigned int mph_ii_d; /* Management: Info Ind, disconn. */
} isdn_interface_info_t;
ISDN_CHANNEL_STATUS
The ISDN_CHANNEL_STATUS ioctl retrieves the status and statistics
of an ISDN channel. The requesting channel must own the channel
whose status is being requested or the ioctl will fail. fd is any
file descriptor. arg is a pointer to a struct isdn_channel_info. If
the interface field is set to ISDN_CHAN_SELF, it will be changed in
the returned structure to reflect the proper device-specific chan‐
nel of the requesting fd.
typedef struct isdn_channel_info {
isdn_chan_t channel;
enum isdn_iostate iostate;
struct isdn_io_stats {
ulong_t packets; /* packets transmitted or received */
ulong_t octets; /* octets transmitted or received */
ulong_t errors; /* errors packets transmitted or received */
} transmit, receive;
} isdn_channel_info_t;
ISDN_PARAM_SET
fd is the file descriptor for a management device. arg is a pointer
to a struct isdn_param. This command allows the setting of various
ISDN physical layer parameters such as timers. This command uses
the same arguments as the ISDN_PARAM_GET command.
ISDN_PARAM_GET
fd is the file descriptor for a management device. arg is a pointer
to a struct isdn_param This command provides for querying the value
of a particular ISDN physical layer parameter.
typedef enum {
ISDN_PARAM_NONE = 0,
ISDN_PARAM_NT_T101, /* NT Timer, 5-30 s, in milliseconds */
ISDN_PARAM_NT_T102, /* NT Timer, 25-100 ms, in milliseconds */
ISDN_PARAM_TE_T103, /* TE Timer, 5-30 s, in milliseconds */
ISDN_PARAM_TE_T104, /* TE Timer, 500-1000 ms, in milliseconds */
ISDN_PARAM_MAINT, /* Manage the TE Maintenance Channel */
ISDN_PARAM_ASMB, /* Modify Activation State Machine Behavior */
ISDN_PARAM_POWER, /* Take the interface online or offline */
ISDN_PARAM_PAUSE, /* Paused if == 1, else not paused == 0 */
} isdn_param_tag_t;
enum isdn_param_asmb {
ISDN_PARAM_TE_ASMB_CCITT88, /* 1988 bluebook */
ISDN_PARAM_TE_ASMB_CTS2, /* Conformance Test Suite 2 */
};
typedef struct isdn_param {
isdn_param_tag_t tag;
union {
unsigned int us; /* micro seconds */
unsigned int ms; /* Timer value in ms */
unsigned int flag; /* Boolean */
enum isdn_param_asmb asmb;
enum isdn_param_maint maint;
struct {
isdn_chan_t channel; /* Channel to Pause */
int paused; /* TRUE or FALSE */
} pause;
unsigned int reserved[2]; /* reserved, set to zero */
} value;
} isdn_param_t;
ISDN_PARAM_POWER
If an implementation provides power on and off functions, then
power should be on by default. If flag is ISDN_PARAM_POWER_OFF then
a TE interface is forced into state F0, NT interfaces are forced
into state G0. If flag is ISDN_PARAM_POWER_ON then a TE interface
will immediately transition to state F3 when the TE D-channel is
opened. If flag is one, an NT interface will transition to state G1
when the NT D-channel is opened.
Implementations that do not provide ISDN_POWER return failure with
errno set to ENXIO.ISDN_POWER is different from ISDN_PH_ACTI‐
VATE_REQ since CCITT specification requires that if a BRI-TE inter‐
face device has power, then it permits activation.
ISDN_PARAM_NT_T101
This parameter accesses the NT timer value T1. The CCITT recommen‐
dations specify that timer T1 has a value from 5 to 30 seconds.
Other standards may differ.
ISDN_PARAM_NT_T102
This parameter accesses the NT timer value T2. The CCITT recommen‐
dations specify that timer T2 has a value from 25 to 100 millisec‐
onds. Other standards may differ.
ISDN_PARAM_TE_T103
This parameter accesses the TE timer value T3. The CCITT recommen‐
dations specify that timer T3 has a value from 5 to 30 seconds.
Other standards may differ.
ISDN_PARAM_TE_T104
This parameter accesses the TE timer value T4. The CTS2 specifies
that timer T4 is either not used or has a value from 500 to 1000
milliseconds. Other standards may differ. CTS2 requires that timer
T309 be implemented if T4 is not available.
ISDN_PARAM_MAINT
This parameter sets the multi-framing mode of a BRI-TE interface.
For normal operation this parameter should be set to
ISDN_PARAM_MAINT_ECHO. Other uses of this parameter are dependent
on the definition and use of the BRI interface S and Q channels.
ISDN_PARAM_ASMB
There are a few differences in the BRI-TE interface activation
state machine standards. This parameter allows the selection of the
appropriate standard. At this time, only
ISDN_PARAM_TE_ASMB_CCITT88 and ISDN_PARAM_TE_ASMB_CTS2 are avail‐
able.
ISDN_PARAM_PAUSE
This parameter allows a management device to pause the IO on a B-
channel. pause.channel is set to indicate which channel is to be
paused or un-paused. pause.paused is set to zero to un-pause and
one to pause. fd is associated with an ISDN interface management
device. arg is a pointer to a struct isdn_param.
ISDN_SET_LOOPBACK
fd is the file descriptor for an ISDN interface's management
device. arg is a pointer to an isdn_loopback_request_t structure.
typedef enum {
ISDN_LOOPBACK_LOCAL,
ISDN_LOOPBACK_REMOTE,
} isdn_loopback_type_t;
typedef enum {
ISDN_LOOPBACK_B1 = 0x1,
ISDN_LOOPBACK_B2 = 0x2,
ISDN_LOOPBACK_D = 0x4,
ISDN_LOOPBACK_E_ZERO = 0x8,
ISDN_LOOPBACK_S = 0x10,
ISDN_LOOPBACK_Q = 0x20,
} isdn_loopback_chan_t;
typedef struct isdn_loopback_request {
isdn_loopback_type_t type;
int channels;
} isdn_loopback_request_t;
An application can receive D-channel data during D-Channel loopback
but cannot transmit data. The field type is the bitwise OR of at
least one of the following values:
ISDN_LOOPBACK_B1 (0x1) /* loopback on B1-channel */
ISDN_LOOPBACK_B2 (0x2) /* loopback on B2-channel */
ISDN_LOOPBACK_D (0x4) /* loopback on D-channel */
ISDN_LOOPBACK_E_ZERO (0x8) /* force E-channel to Zero if */
/* fd is for NT interface */
ISDN_LOOPBACK_S (0x10) /* loopback on S-channel */
ISDN_LOOPBACK_Q (0x20) /* loopback on Q-channel */
ISDN_RESET_LOOPBACK
arg is a pointer to an isdn_loopback_request_t structure.
ISDN_RESET_LOOPBACK turns off the selected loopback modes.
ISDN Data Format
The isdn_format_t type is meant to be a complete description of the
various data modes and rates available on an ISDN interface. Several
macros are available for setting the format fields. The isdn_format_t
structure is shown below:
/* ISDN channel data format */
typedef enum {
ISDN_MODE_NOTSPEC, /* Not specified */
ISDN_MODE_HDLC, /* HDLC framing and error checking */
ISDN_MODE_TRANSPARENT /* Transparent mode */
} isdn_mode_t;
/* Audio encoding types (from audioio.h) */
#define AUDIO_ENCODING_NONE (0) /* no encoding*/
#define AUDIO_ENCODING_ULAW (1) /* mu-law */
#define AUDIO_ENCODING_ALAW (2) /* A-law */
#define AUDIO_ENCODING_LINEAR (3) /* Linear PCM */
typedef struct isdn_format {
isdn_mode_t mode;
unsigned int sample_rate; /* sample frames/sec*/
unsigned int channels; /* # interleaved chans */
unsigned int precision; /* bits per sample */
unsigned int encoding; /* data encoding */
} isdn_format_t;
/*
* These macros set the fields pointed
* to by the macro argument (isdn_format_t*)fp in preparation
* for the ISDN_SET_FORMAT ioctl.
*/
ISDN_SET_FORMAT_BRI_D(fp) /* BRI D-channel */
ISDN_SET_FORMAT_PRI_D(fp) /* PRI D-channel */
ISDN_SET_FORMAT_HDLC_B64(fp) /* BRI B-ch @ 56kbps */
ISDN_SET_FORMAT_HDLC_B56(fp) /* BRI B-ch @ 64kbps */
ISDN_SET_FORMAT_VOICE_ULAW(fp) /* BRI B-ch voice */
ISDN_SET_FORMAT_VOICE_ALAW(fp) /* BRI B-ch voice */
ISDN_SET_FORMAT_BRI_H(fp) /* BRI H-channel */
ISDN Datapath Types
Every STREAMS stream that carries data to or from the ISDN serial
interfaces is classified as a channel-stream datapath. A possible ISDN
channel-stream datapath device name for a TE could be
/dev/isdn/0/te/b1.
On some hardware implementations, it is possible to route the data from
hardware channel to hardware channel completely within the chip or con‐
troller. This is classified as a channel-channel datapath. There does
not need to be any open file descriptor for either channel in this con‐
figuration. Only when data enters the host and utilizes a STREAMS
stream is this classified as an ISDN channel-stream datapath.
ISDN Management Stream
A management stream is a STREAMS stream that exists solely for control
purposes and is not intended to carry data to or from the ISDN serial
interfaces. A possible management device name for a TE could be
/dev/isdn/0/te/mgt.
Channel Management IOCTLS
The following ioctls describe operations on individual channels and the
connection of multiple channels.
ISDN_SET_FORMAT
fd is a data channel, the management pseudo-channel associated with
the data channel, or the management channel associated with the
data channel's interface or controller. arg is a pointer to a
struct isdn_format_req. The ISDN_SET_FORMAT ioctl sets the format
of an ISDN channel-stream datapath. It may be issued on both an
open ISDN channel-stream datapath Stream or an ISDN Management
Stream. Note that an open(2) call for a channel-stream datapath
will fail if an ISDN_SET_FORMAT has never been issued after a
reset, as the mode for all channel-stream datapaths is initially
biased to ISDN_MODE_NOTSPEC. arg is a pointer to an ISDN format
type (isdn_format_req_t*).
typedef struct isdn_format_req {
isdn_chan_t channel;
isdn_format_t format; /* data format */
int reserved[4]; /* future use - must be 0 */
} isdn_format_req_t;
If there is not an open channel-stream datapath for a requested
channel, the default format of that channel will be set for a sub‐
sequent open(2).
To modify the format of an open STREAM, the driver will disconnect
the hardware channel, flush the internal hardware queues, set the
new default configuration, and finally reconnect the data path
using the newly specified format. Upon taking effect, all state
information will be reset to initial conditions, as if a channel
was just opened. It is suggested that the user flush the interface
as well as consult the hardware specific documentation to insure
data integrity.
If a user desires to connect more than one B channel, such as an H-
channel, the B-channel with the smallest offset should be speci‐
fied, then the precision should be specified multiples of 8. For an
H-channel the precision value would be 16. The user should subse‐
quently open the base B-channel. If any of the sequential B-chan‐
nels are busy the open will fail, otherwise all of the B-channels
that are to be used in conjunction will be marked as busy.
The returned failure codes and their descriptions are listed below:
EPERM /* No permission for intented operation */
EINVAL /* Invalid format request */
EIO /* Set format attempt failed. */
ISDN_SET_CHANNEL
The ISDN_SET_CHANNEL ioctl sets up a data connection within an ISDN
controller. The ISDN_SET_CHANNEL ioctl can only be issued from an
ISDN management stream to establish or modify channel-channel data‐
paths. The ioctl parameter arg is a pointer to an ISDN connection
request (isdn_conn_req_t*). Once a data path is established, data
flow is started as soon as the path endpoints become active. Upon
taking effect, all state information is reset to initial condi‐
tions, as if a channel was just opened.
The isdn_conn_req_t structure is shown below. The five fields
include the receive and transmit ISDN channels, the number of
directions of the data path, as well as the data format. The
reserved field must always be set to zero.
/* Number of directions for data flow */
typedef enum {
ISDN_PATH_NOCHANGE = 0, /* Invalid value */
ISDN_PATH_DISCONNECT, /* Disconnect data path */
ISDN_PATH_ONEWAY, /* One way data path */
ISDN_PATH_TWOWAY, /* Bi-directional data path */
} isdn_path_t;
typedef struct isdn_conn_req {
isdn_chan_t from;
isdn_chan_t to;
isdn_path_t dir; /* uni/bi-directional or disconnect */
isdn_format_t format; /* data format */
int reserved[4]; /* future use - must be 0 */
} isdn_conn_req_t;
To specify a read-only, write-only, or read-write path, or to dis‐
connect a path, the dir field should be set to ISDN_PATH_ONEWAY,
ISDN_PATH_TWOWAY , and ISDN_PATH_DISCONNECT respectively. To mod‐
ify the format of a channel-channel datapath, a user must discon‐
nect the channel and then reconnect with the desired format.
The returned failure codes and their descriptions are listed below:
EPERM /* No permission for intented operation */
EBUSY /* Connection in use */
EINVAL /* Invalid connection request */
EIO /* Connection attempt failed */
ISDN_GET_FORMAT
The ISDN_GET_FORMAT ioctl gets the ISDN data format of the channel-
stream datapath described by fd. arg is a pointer to an ISDN data
format request type (isdn_format_req_t*). ISDN_GET_FORMAT can be
issued on any channel to retrieve the format of any channel it
owns. For example, if issued on the TE management channel, the for‐
mat of any other te channel can be retrieved.
ISDN_GETCONFIG
The ISDN_GETCONFIG ioctl is used to get the current connection sta‐
tus of all ISDN channels associated with a particular management
STREAM. ISDN_GETCONFIG also retrieves a hardware identifier and the
generic interface type. arg is an ISDN connection table pointer
(isdn_conn_tab_t*). The isdn_conn_tab_t structure is shown below:
typedef struct isdn_conn_tab {
char name[ISDN_ID_SIZE]; /* identification string */
isdn_interface_t type;
int maxpaths; /* size in entries of app's array int npaths; */
/* number of valid entries returned by driver */
isdn_conn_req_t *paths; /* connection table in app's memory */
} isdn_conn_tab_t;
The table contains a string which is the interface's unique identi‐
fication string. The second element of this table contains the ISDN
transmit and receive connections and configuration for all possible
data paths for each type of ISDN controller hardware. Entries that
are not connected will have a value of ISDN_NO_CHAN in the from and
to fields. The number of entries will always be ISDN_MAX_CHANS, and
can be referenced in the hardware specific implementation documen‐
tation. An isdn_conn_tab_t structure is allocated on a per con‐
troller basis.
SEE ALSOgetmsg(2), ioctl(2), open(2), poll(2), read(2), write(2), audio(7I),
dbri(7D), streamio(7I)
ISDN, An Introduction - William Stallings, Macmillan Publishing Com‐
pany. ISBN 0-02-415471-7
SunOS 5.10 7 Apr 1998 isdnio(7I)
