Technical data

SunOS 5.5 Ioctl Requests isdnio(7I)
NAME isdnio − 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 argu-
ments 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 determines the control func-
tion to be performed as described in theIOCTLS section of this document. arg represents
additional information that is needed by command. The type of arg depends upon the
command, but generally it is an integer or a pointer to a command-specific data structure.
Since theseISDN commands are a subset of ioctl and streamio(7I), they are subject to
errors as described in those interface descriptions.
This set of genericISDN 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 pro-
vides one or more ISDN interfaces and zero or more auxiliary interfaces. In this context,
the term interface 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 Division Multiplexed
Serial Interfaces. As an example, a Basic Rate ISDN (BRI) Terminal Equipment (TE) inter-
face 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 inter-
face.
Basic Rate ISDN A Basic Rate ISDN (BRI) interface consists of a 16000 bit per second Delta Channel (D-
channel) for signalingand X.25 packet transmission, and two 64000 bit per second Bearer
Channels (B-channels) for transmission of voice or data.
modified 7 Apr 1994 7I-151