W91031 Datasheet, PDF (27/29 Pages) Winbond – LOW POWER CMOS INTERGRATED CIRCUIT

Preliminary W91031
CPE goes off-hook
CPE mutes handset & disables keypad
Start Point
CPE sends
Tip/Ring
Alert Signal
ACK
Mark
Note 1
A
B
Note 3
C
D
E
F
Note 6
SLEEP
CPE unmutes handset
and enables keypad
Message
G
H
INTN
...
t
REC
t
ABS
ALGO
FSKE
Note 2
Note 4
Note 5
FCDN
FDRN
...
DCLK
DATA
Data
Figure 9-6. Input and Output Timing of BT Loop State (Off-hook) Data Transmission
A = 40−50 mS
C = ≤ 100 mS
E = 5−100 mS
G = Depends on data length
B = 80−85 mS
D = 65−75 mS
F = 45−75 mS
H ≤ 100 mS
Notes:
1. In a CPE where AC power is not available, the designer may choose to switch over to line power when the CPE goes
off-hook and use battery power while on-hook.
2. The FSKE pin should be set low to enable the alert tone detector when the dual tone alert signal is expected.
3. The exchange will have already disabled the speech path to the distant customer in both transmission directions.
4. The FSKE may be set high as soon as the CPE has finished sending the acknowledge signal ACK.
5. FSKE should be set low when FCDN has become inactive.
6. In unsuccessful attempts where the exchange does not send the FSK signal, the CPE should disable FSKE, unmute the
handset and enable the keypad after this interval.
- 27 -
Publication Release Date: August 2000
Revision A1