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Table 2-2.
Clock Ring Indicators
CLOCK RING Indicator
8
7
6
S
4
3
2
1
Time
0
0
0
0
0
0
0
1
TO
0
0
0
0
0
0
1
1
Tl
0
0
0
0
0
0
1
0
T2
0
0
0
0
0
1
1
0
T3
0
0
0
0
0
1
0
0
T4
0
0
0
0
1
1
0
0
TS
0
0
0
0
1
0
0
0
T6
0
0
0
1
1
0
0
0
T7
0
0
0
1
o .
0
0
0
T8
0
0
1
1
0
0
0
0
T9
0
0
1
0
0
0
0
0
TlO
0
1
1
0
0
0
0
0
Tll
0
1
0
0
0
0
0
0
Tl2
1
1
0
0
n
0
0
0
Tl3
1
0
0
0
0
0
0
0
T14
1
0
0
0
0
0
0
1
TlS
Clock Ring
The Clock Ring indicators show the status of the
I-Mc clock ring (Table 2-2), which provides the
basic timing signals for the 2702.
The CO Clock Ring indicator is lit when the clock-
ring timing signals are being generated during CO
time, and is extinguished during Cl time.
C-Clk B Dr
This indicator is lit by each B-time clock-ring step-
ping pulse.
This indicator is lit at a 2-usec rate in normal
clock-ring operation and complemented at the rate
that the Single Cycle pushbutton is depressed if the
Clock switch is activated (clock-test mode).
Binary Clock
These indicators show the binary address of the LCW
being processed.
The 1, 2,
4,
and
8
indicators are used in the basic
2702; all five indicators (16 included) are used in a
2702 with the 31-Line Expansion feature.
Indicator 16 is active when the 31-Line Expansion
feature is installed.
2-8
These indicators show the address of the SLCW being
processed.
These indicators are active when the Speed Exten-
sion or 31-Line Expansion feature is installed.
Wrap Chk
This indicator lights during a wrap test if the character
rroeived does not compare with the character transmitted.
Off-Line Test
This lights when the 2702 is logically disconnected from
the
I/o
interface by setting the Off- Line Test/Normal
switch to Off-Line Test, or the Meter switch on the
operator's panel to OFF, and by the processor's having
been in a wait or halt state after the switches were set.
CE Test
This indicator lights whenever the CE Test switch is
depressed.
C-Clk Check
This indicator lights when a clock-ring check fails.
The clock ring is checked during A time to verify
that one odd and one even position are set and during
B time to verify that only one position is set.
S-Clk Check
This indicator lights when the S binary-clock address
is not zero when the C binary-clock address is zero
--that is, a normal matched scan does not occur at
C binary-clock address zero.
Test Ll and Test L2
The Test Ll indicator lights when the Ll test bit does
not compare with the high-order bit of the binary clock.
The Test L2 indicator lights when the
L2
test bit
does not compare with the high-order bit of the binary
clock.
Cmnd Cycle
This indicator is lit when· the interface controls
start an initial-selection sequence, and is extinguished
when the initial-selection sequence is completed.
Unit Busy
This indicator lights when the command register con-
tains a command that is waiting to be loaded into
an
LCW.
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