CPC7583
20 Hz ringing hold this input state for 25 ms. During
this hold period, toggle the inputs from the ringing
state to the talk state. After the 25 ms, release T to
SD
return switch control to the input pins IN
,
TESTout
IN
, IN
and the latch control pin.
RINGING
TESTin
2.2.1 Make-Before-Break Operation (Ringing to Talk Transition)
Break
Ring
Switches Return Access
Ring All Other
IN
IN
IN
T
SD
State
Latch
Timing
Test
1 and 2 Switch 3 Switch 4 Switches
RINGING
TESTIN
TESTOUT
Ringing
1
0
0
Floating
-
Off
On
On
Off
On
On
Off
SW4 waiting for next
zero-current crossing to turn
off. Maximum time is one-half
of ringing. In this transition
Make-
before-
break
0
0
0
Floating state, current that is limited to
the dc break switch current
limit value will be sourced
from the ring node of the
SLIC.
Off
0
Zero-cross current has
Talk
0
0
0
Floating
occurred
On
Off
Off
Off
2.2.2 Break-Before-Make Operation (Ringing to Talk Transition)
Break
Ring
Ring All Other
Test
1 and 2 Switch 3 Switch 4 Switches
IN
IN
IN
T
SD
State
Latch
Timing
Switches Return Access
RINGING
TESTIN
TESTOUT
Ringing
All off
1
1
0
0
0
1
Floating
-
Off
On
On
Off
Hold this state for one-half of
Floating ringing cycle. SW4 waiting for
zero current to turn off.
Off
Off
On
Off
0
Zero current has occurred.
Floating
All off
Talk
1
0
0
0
1
0
Off
On
Off
Off
Off
Off
Off
Off
SW4 has opened
Floating
Close break switches
2.3 Alternate Break-Before-Make Operation
Note that break-before-make operation can also be
2.4 Data Latch
The CPC7583 has an integrated data latch. The latch
achieved using T as an input. In lines 2 and 3 of the
operation is controlled by logic-level input at the
SD
LATCH pin. The data input of the latch are the input
pins, while the output of the data latch is an internal
node used for state control. When the LATCH control
pin is at logic 0, the data latch is transparent and data
control signals flow directly through to state control. A
change in input will be reflected by a change in switch
state. When the LATCH control pin is at logic 1, the
data latch is active and a change in input control will
not affect switch state. The switches will remain in the
position they were in when the LATCH changed from
table “Break-Before-Make Operation (Ringing to Talk
Transition)” on page 15, instead of using the logic input
pins to force the all-off state, force T to ground. This
SD
overrides the logic inputs and also forces the all off
state. Hold this state for one-half of the ringing cycle.
During this T forced all-off state, change the inputs
SD
from the power ringing state (IN
= 1, IN
= 0,
RING
TESTIN
IN
IN
= 0) to the talk state (IN
= 0,
TESTOUT
RING
= 0, IN
= 0). After the hold period,
TESTIN
TESTOUT
release T to return switch control to the input pins
SD
which will set the talk state.
R06
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