AT&T 1987 AT&T Telephone User Manual


 
Setup mode is entered.
f. Data Call Setup Mode
Data Call Setup Mode is a transitional state entered after Transfer To Data, Data
Terminal Dialing, or during auto-answer;
it exists during the handshake between
data ports.
If the endpoints are compatible and handshaking is successful, a data connection is
established. If handshake failure occurs, the user is notified and the data endpoint
returns to the Idle mode. Successful handshake must occur within 15 seconds of
answer at the called data endpoint.
This implies that the voice terminal user must
invoke Transfer To Data within 15 seconds after far-end answer. Similarly, if an
originating voice user calls a voice terminal and both users transfer to data, both
ends must transfer within the 15 second time limit.
If the data endpoint is optioned for Command Mode permission, the data endpoint
will receive call progress text messages while in the Data Call Setup mode.
g. Data Mode
Data Mode is first entered after successful completion of Data Call Setup.
Transparent communication between connected endpoints is provided in Data
Mode.
Connecting Configurations
Refer to “Connectivity” in Section 4 for data equipment connections.
Controlling Features
It is possible to originate data calls from a voice terminal with a Transfer to Data button or
from data endpoints that support Command Mode (i.e.,
ASCII data terminals with keyboards
and host computers). Several controlling features are provided to allow data endpoints and
voice terminals to set up data calls.
The following briefly describes the Data Service
features used in controlling data calls:
a. Command Mode/Expert Mode
Command Mode and Expert Mode provide an interface to the Data Terminal
Dialing feature, the Third-Party Call Setup feature (V2), and permits users to
display and change (V2 only) data port options.
b. Data Terminal Dialing
Data Terminal Dialing provides call setup from terminals and host computers.
c. Transfer To Data
Transfer To Data is the preferred method of data call origination from multiline
voice terminals equipped with Transfer to Data (DATA) buttons and associated
digital data endpoints.
The DATA button is associated by DDC with a near end
data endpoint. A unique DATA button must be provided for each DDC that the
voice terminal is capable of controlling.
Associated with each DATA button is an
LED that reflects the status of data endpoints as follows:
Dark–Data endpoint is idle
Winking–Data endpoint is reserved (preindicated)
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