Communications Device Interface (CDI)

CDI

Section: Communications Device Interface (CDI) (7)
Updated: 2008-10-31
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NAME

CDI - Communications Device Interface

SYNOPSIS

#include <sys/cdi.h>

OVERVIEW

The Communications Device Interface (CDI) is a low-level device interface that is defined between a user and a provider using STREAMS(4) and the putmsg(2) and getmsg(2) system calls.

DESCRIPTION

Local Manaement Primitives

The following management primitives are common to all styles of communication providers and devices.

CD_INFO_REQ(7): Requests information concerning the communications device, provider limits, styles and features.
CD_INFO_ACK(7): Provides information concerning the communications device, provider limits, styles and features.
CD_ATTACH_REQ(7): Requests that a Style 2 communications device provider be attached to the speciifed physical point of appearance (PPA).
CD_DETACH_REQ(7): Requests that a Style 2 communications device provider be detached from the attached physical point of appearance (PPA).
CD_OK_ACK(7): Provides positive acknowledgment of request primitives that require acknowledgment.
CD_ERROR_ACK(7).: Provides negative acknowledgment of request primitives that require acknowledgment.

Device Connection Primitives

The following primitves enable and disable the communications device for transmission.

CD_ENABLE_REQ(7): Requests that the communications device be enabled on the attached physical point of appearance and with an optional dial string.
CD_ENABLE_CON(7): Provides confirmation of the CD_ENABLE_REQ(7) primitive.
CD_DISABLE_REQ(7): Requests that the communications device be disabled on the attached physical point of appearance.
CD_DISABLE_CON(7).: Provides confirmation of the CD_DISABLE_REQ(7) primitive.

Device Data Transfer Primitives

The following primitives provide for the indication of errors associated with received or transmitted data.

CD_ERROR_IND(7): Provides indication of an error in the input or output section.
CD_BAD_FRAME_IND(7): Provides indication of a frame received in error.

The following primitives provide for the reception of data.

CD_READ_REQ(7): Requests that the communications device read received data within the timeout specified, and then convert the input section to output.
CD_ALLOW_INPUT_REQ(7): Requests that the input section be enabled until the next CD_HALT_INPUT_REQ(7).
CD_HALT_INPUT_REQ(7): Requests that the input section be disabled until the next CD_ALLOW_INPUT_REQ(7).
CD_UNITDATA_IND(7): Provides indication of received data.

The following primitives provide for the transmission of data.

CD_UNITDATA_REQ(7): Requests the transmission of data.
CD_UNITDATA_ACK(7): Acknowledges the transmission of data or provides timing clues for paced output.
CD_ABORT_OUTPUT_REQ(7): Aborts the output of data.

The following primitives provide for the synchronized transmission and reception of data on half-duplex communications devices.

CD_WRITE_READ_REQ(7).: Requests that a combination of write and read be performed.

Leads and Signals

The following primitives provide the CD user with the ability to manage modem leads and signals.

CD_MODEM_SIG_IND(7): Provides an indication of the current state of leads and signals.
CD_MODEM_SIG_POLL(7): Requests that the communications device provider reply with a CD_MODEM_SIG_IND(7) indicating the current state of modem leads and signals.
CD_MODEM_SIG_REQ(7): Requests that the specified leads and signals be asserted or deasserted.

Miscellaneous

CD_MUX_NAME_REQ(7) Not documented.

HISTORY

The Communications Device Interface first appeared in SVR 4[1].

CONFORMANCE

This interface conforms to CDI with Gcom extensions.

REFERENCES

[1]: SVR 4, UNIX® System V Release 4 Programmer's Manual, 1990, (Englewood Cliffs, New Jersey), AT&T UNIX System Laboratories, Inc., Prentice Hall.
[2]: Magic Garden, The Magic Garden Explained: The Internals of UNIX® System V Release 4 / An Open Systems Design, 1994, (Australia), B. Goodheart, J. Cox, Prentice Hall. [ISBN 0-13-098138-9]
[3]: Advanced Programming in the UNIX®Environment, 15th edition, December 1997, (Reading, Massachusetts), W. R. Stevens, Addison Wesley. [ISBN 0-201-56317-7]