AT&T AT&T manual Data Endpoint States, Data Call Processing Modes

Data Endpoint States

The data endpoint may take on three states: (l) off-line, (.2) on-line (on-hook), and (3) on-line (off-hook). Off-line is when a data terminal is out of service (turned off, disconnected, etc,). The on-line (on-hook) state occurs when the terminal is turned on, is available to answer a call, but is not on a data call. Finally, the on-line (off-hook) state is when the data endpoint is actively on a data call.

Data Call Processing Modes
Data calls differ		both in signaling and call setup from voice calls. For this reason, a unique
set of	data call	processing	modes have	been defined to support data call operation in a
manner	consistent	with the	characteristics	of data terminals.

a.Off-Line Mode

The data endpoint is considered to be in the Off-Line Mode whenever the data endpoint’s DTR signal is inactive (e.g., “turned off”). The endpoint is considered unavailable and calls to this endpoint will receive the “RINGING” message or Ringback (indefinitely).

b. Idle Mode

The Idle Mode indicates that the data endpoint is in its on-line, on-hook state. While idle, call processing will allow the endpoint to:

— Enter either Data Terminal Dialing mode to originate a data call, or enter the Setup mode after a call is originated from a voice terminal (Transfer To Data) or other data terminal (Third-Party Call Setup; V2 only).

—Autoanswer a data call and go into Setup mode.

The	data	endpoint	remains in the Idle mode while the user is establishing a data
call	from	a voice	terminal until Transfer To Data is activated.

c. Command Mode

Command Mode enables the Data Terminal Dialing feature, allows the user to view and change (V2 only) associated data port options, and provides access to the Third-party Call Setup feature (V2). Command Mode may be entered by going on- line and pressing Break or Break-Return.

d .Expert Mode is an enhancement to the Command Mode feature that provides an alternative method of performing the full range of Command Mode functions. By eliminating the display of menus and allowing multiple commands to be entered on a single line, Expert Mode lends itself to computer-driven instructions. Individual users who are very familiar with Command Mode operations may also find it useful.

e. Data Terminal Dialing Mode

Data Terminal Dialing is a data feature accessed via Command Mode. It provides a procedure to establish data calls without the use of a voice terminal. Data Terminal Dialing supports both on-premises and off-premises data calls (with the support of the System 25 Modem Pooling feature). Dialed digits are entered from the data terminal keyboard or host computer (using a program compatible with Data Terminal Dialing protocol). Call progress text messages are sent to the terminal in place of call progress tones. Upon completion of digit entry, Data Call

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