Operator Panel - IBM 3274 51C Maintenance Information

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Description
On/Off switch:
III
=
On;
lQJ
=
Off.
On indicator: Indicates the 3274 is on.
IML (Initial Machine Load) pushbutton: Pressing
and holding causes a basic test to run. When the
pushbutton is released, IML tests start. At com-
pletion, the machine is loaded.
Alt IML Address switch:
• Position 1: Holding, while pressing the IBM push-
button, bypasses the tests and loads the
machine directly. Use only after normal
IML fails.
• Position 2: Holding, while pressing the IML push-
button, invokes the adapter and wrap
test.
Holding the Alt IML Address switch in
position 2 will cause the modem self-test
to be initiated and repeated
approximately every 4 seconds, until the
switch is released.
IJ
m
8 4 2 1 Indicators: These light while the IML push-
button is held. During IML, they follow the test
sequence. At completion, they all go out. During
operation, they indicate operational status.
Encrypt/Decrypt Key Switch - Allows
a
new master
key to be entered when in the horizontal position.
Encrypt/Decrypt Battery - Allows the master key to
be maintained in the 3274 when power is off.
Operate - This indicator shows that the Integrated
Modem is ready to exchange data with the attached
TP network.
Test - This indicator is on when the Integrated
Modem is in test mode. Test mode is entered when-
ever the self-test is running or by a test function
being run from the central site modem or when the
link problem determination aid (LPDA) host invoked
diagnostics are running.
Data Quality (Good/Poor) - These indicators light
according to the errors detected in the receive signal
(caused by TP line quality deterioration). The fol-
lowing chart shows the state of the Data Quality
indicators.
Good
Poor
l
Meaning
On
Off
- Good signal quality
(no errors) .
Flashing Off or flashing - Marginal signal qual-
ity (3 bit errors per
second) .
Off On or flashing - Poor signal quality
(6 bit errors per
second)
Off Off
- No signal being
received.
Modem Address Switches (8) - These eight switches
provide the address for host-invoked LPDA diagnostic
tests. The address switches should correspond to the
3274 address that was customized.
lWhen running the self-test by using the ALT 2 switch,
the Poor indicator should light if the self-test is
failing.
Note: The indicator turns off when the switch is
released.
Figure D-6. 3274 Operator Panel - Model 51 C with 2400-, 4800-, or 9600-bps Integrated Modem
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