1. If the data set has power off.
2. If the data set is not in data mode.
3. For the Read, Poll, and Inhibit commands only,
if a continuous Space signal is received for
one character time or greater.
This bit is never set under the Wrap, Enable, Disable,
or Sense commands.
4-Bit--Data Check This bit is set:
1. During the execution of the Read or Inhibit
command if the line is in text-out mode and ® is received. It indicates that the remote
terminal detected a VRC error in the last block
of data received.
2. For the Read, Inhibit, and Poll commands if
the line is at Space at stop-bit time (the 2703 is out of sync).
3. When the line is executing Poll, Write, or
Wrap if a VRC error is detected in one of the
ch ... .racters being transmitted.
4. During a Read, Poll, or Inhibit when a VRC error is detected.
5. If the response to a Poll command is not © or ®. This bit is not set during the execution of the Dial,
Prepare, Enable, Disable, or Sense commands.
7-Bit--Timeout
This sense bit is set:
1. During the execution of the Read command if
no characters are received for a continuous
period of three seconds when the line is either
in control mode or its receive-control bit is OFF. Otherwise, the 28-second timeout
applies.
2. During the execution of Prepare if a continuous Space signal is received for a period of more
than 28 seconds.
3. During a Poll command if no characters are
received for a continuous period of three
seconds when the receive-control bit is ON. This sense bit is not set while the line is executing
Disable, Write, Wrap, Enable, Break, Inhibit, Sense, or Search. Telegraph Terminal Control Type I O-Bit--Command Reject.
This bit is set during initial selection by the inter­
face controls:
1. If a command that is not defined or cannot be
executed by the 2703 is presented. This occurs
if the Dial command is issued and the Autocall
Adapte r has not been installed in the 2703. The
Dial command is accepted but then rejected if
issued to a line not associated with an instal­
led Autocall Adapter.
2. If a Poll command is issued to a line controlled
by Telegraph Terminal Control Type 1. This sense bit w ill not be set during the execution of
the Read, Write, Prepare, Wrap, Enable, Disable,
Inhibit, Sense, Search, or Break commands.
1-Bit--Intervention Required
This sense bit is set:
1. To indicate that the addressed line has not been
enabled, if the Read, Inhibit, Write, Prepare,
Break, or Search command is being executed.
2. If a continuous Space signal is received for
one character time or greater during the
execution of Read, Inhibit, or Search. This bit is never set during the execution of the
Dial, Wrap, Enable, Disable, Poll, or Sense com­
mands.
4-Bit--Data Check This bit is set:
1. During the execution of Read, Inhibit, or Search if the line is at Space at stop-bit time.
2. During the execution of Write or Break if an
echo check occurs.
This sense bit is not set under the Dial, Prepare,
Enable, Disable, or Sense commands.
7 -Bit--Timeout
This sense bit is set:
1. During the execution of Read or Search if no
characters are received for a continuous
period of more than 28 seconds when the
receive-control bit is ON, or tw.o seconds if
this bit is OFF. 2. During the execution of Prepare if a continuous Space signal has been received for more than
28 seconds.
This sense bit is never set under the Write, Wrap,
Dial, Disable, Enable, Break, Inhibit, Poll, or Sense commands.
Telegraph Terminal Control Type IT O-Bit--Command Reject
This bit is set during initial selection by the inter­
face controls:
1. If a command that is not defined or cannot be
executed by the 2703 is presented. This
occurs if the Dial command is issued and the
33

Aut')call Adapter has not been installed in the 2703. The Dial command is accepted but then
rejected if issued to a line not associated with
an installed Autocall Adapte r.
2. For Poll or Search. This sense bit is not set during the execution of the
Read, Write, Prepare, Wrap, Enable, Disable, Inhibit, Sense, or Break commands.
1-Bit--Intervention Required
If a Read, Inhibit, Write, or Prepare command is
being executed and the addressed line has a data line
set attached, this bit is set:
1. If the data set has its powe r off.
2. If the data set is lion-hook. " 3. If the data set is not in data mode (is in either
test or talk mode).
4. If the data set is not attached.
5. For the Read and Inhibit commands only, if a
continuous Space signal is received for one
character time or greater.
6. If Dial is being executed, if the ACU's Power
Indicator is OFF.
7. During the Dial command if an ACU is not
attached for thi::, line.
This bit is not set for the Wrap, Enable, Disable, Sense, Poll, or Search commands.
4-Bit--Data Check This sense bit is set:
1. During the execution of Read and Inhibit if the
line is at Space at stop-bit time (the 2703 is out
of sync).
2. If the line is executing Write and a Break signal
is received over the Received Data line.
This bit is never set under the Dial, Enable, Prepare, Break, Wrap, Disable, Sense, Search, or Poll commands.
7 -Bit--Timeout
This sense bit is set:
34
1. During the execution of the Read command if no
characters are received for a continuous
period of 28 seconds.
2. During the execution of Dial if the ACU's Abandon Call and Retry line turns ON. This indicates that the call was not established in the
allotted time and should be redi::i.led. 3. During the execution of Prepare if a continuous Space signal longer than 28 seconds is received.
4. During the execution of Disable if a switched­
network data set does not go "on-hook" within
28 seconds after being signaled to do so. That
is, Data Set Ready does not turn OFF and
end the Disable command within 28 seconds (1\ the time Data Terminal Ready turned OFF. This sense bit is not set during the execution of the Write, Wrap, Enable, Break, Inhibit, Poll. or Sense commands. World Trade Telegraph Terminal Control
O-Bit--Command Reject.
This bit is set during initial selection by the inter­
face controls:
1. If a command that is not defined or cannot be
executed by the 2703 is presented.
2. If a Poll command is issued to a line contl'-::;!L::: by World Trade Telegraph Terminal Control.
This sense bit will not be set during the execution of
the Read, Write, Prepare, \Vrap, Enable, Disable,
Inhibit, Sense, or Break connnands.
1-Bit--Intervention Required
This sense bit is set: 1. To indicate that the addressed line has not
been enabled, if the Read, Inhibit, Write, Pre­ pare, or Break command is being executed.
2. If a continuous Space signal is received for one
character time or greater during the execution
of Read or Inhibit.
This bit is never set during the execution of the Dial, Wrap, Enable, Disable, Poll, or Sense commands.
4-Bit--Data Check This bit is set:
1. During the execution of Read or Inhibit if the
line is at Space at stop-bit time.
2. During the execution of Write or Break if an
echo check occurs.
This sense bit is not set under the Dial, Prepare,
Enable, Disable, or Sense commands.
7 -Bit--Timeout
This sense bit is set:
1. During the execution of Read if no characters
are received for a continuous period of more
than 28 seconds.
2. During the execution of Prepare if a continuous Space signal has been received for more than
28 seconds.
This sense bit is never set under the Write, Wrap, Dial, Disable, Enable, Break, Inhibit, Poll, or Sense commands.