Dial-Up Adapter; Transmit Control (Prerequisite, Dial-Up Adapter Feature) - IBM 2740-1 System Reference Manual

Dial-Up Adapter

With this special feature installed, the 2740 can
communicate with another 2740 terminal or with a
multiplexer over com m on-carrier switched networks.
This feature permits interconnection of the appro­
priate com m on-carrier data set and line facilities
with the terminal. Included with this feature is a
Dial Connect light which is on when a line connection
is established while in the standby status, and a
Dial Disc (disconnect) key which permits disconnect­
ing the terminals at both ends of the line by opera­
ting this key at only one terminal (provided the ter­
minal is not in transmit mode).
NOTE: Disconnecting the terminals at both ends of the line with
the operation of either of the Dial-Disc keys is possible only
if the comm on-carrier data sets have the auto-disconnect
feature installed, o r, in the case of IBM World Trade
machines, the terminal is equipped with the auto-disconnect
special feature.
Once the line connection is established, it remains
intact (regardless of EOT and Bid key operation)
until the Dial Disconnect key is pressed at one of
the two term inals, or until one of the terminals
loses status (see Figures 8 and 9).
nection is established between a terminal and a
Figure 10. Multiplexer Transmit Control (Without Checking)
multiplexer, the multiplexer also has the ability to
disconnect the line.
Any dialed terminal with this feature installed is
prevented from answering if an out-of-paper con­
dition exists, the terminal is in a local mode, or
the terminal power is off (no status). However, if
the terminal is called while operating in the local
mode, the telephone bell sounds at the called te r­
minal (providing the data set has been left in Talk
mode, or in Auto mode if the data set has the Auto­
matic Answering feature installed).
NOTE: This feature cannot be used if the station control special
Transmit Control (Prerequisite, Dial-Up Adapter
Feature)
This special feature permits a multiplexer to con­
trol the send/receive status of a remote terminal.
When the multiplexer transmits a special two-
character control code (/ space), the terminal shifts
to transmit status and sends a
The (B) code shifts the multiplexer to receive status.
(Figures 10 and 11).
If a line con­
SPECIAL FEATURES, MODEL 1
feature is installed.
Special Features, Model 1
to the multiplexer.
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