MT8841
channel seizure
2 sec
Mark state
checksum
TIP/RING
First Ringing
500ms
(min)
Input FSK
Data
200ms
(min)
Second
Ringing
PWDN
t
PU
t
PD
OSC2
CD
*
t
IAL
t
IAH
DATA
High (Input Idle)
High (Input Idle)
DCLK
DR
*
* with external pull-up resistor
Figure 9 - Input and Output Timing (Bellcore CND Service)
start
stop
TIP/RING
b7
t
IDD
start
DATA
b7
stop
1
0
b0 b1 b2 b3 b4 b5 b6 b7
start
stop
1
0
b0 b1 b2 b3 b4 b5 b6 b7
start
stop
1
0
b0 b1 b2
start
b0 b1 b2 b3 b4 b5 b6 b7
stop
b0 b1 b2 b3 b4 b5 b6 b7
start
b0 b1 b2
stop
DCLK
t
CRD
DR *
* with external pull-up resistor
Figure 10 - Serial Data Interface Timing
5-19