EM91810A/B 参数 Datasheet PDF下载

EM91810A/B

TONE/PULSE SWITCHABLE DIALER WITH LCD INTERFACE

Symbol

TONE

Function

Dual Tone Multi-frequency output pin.

In TONE mode, when a entry of digit key (include * , # key), this pin will sent out a corresponding

DTMF signal.

The TONE pin provides minimum tone duration (t

TD

),& minimum intertone pause time to support rapid

key-in. If key-in time is less than t

TD

, DTMF signal will last for t

TD

, otherwise the tone duration will

last as long as the key is pressed.

Handfree input control pin.

Toggle input sturcture, falling edge trigger.

It is used to enable and disable Handfree function.

With waveshaped by a built-in Schmit trigger, the bounce of input can be eliminated by external R,

C debounce circuit.

A built-in pull up resistor is 200K typical.

Handfree output pin.

Inverter output structure (normally "low", active "high").

When a HFI pin is active, Handfree function will be enabled (HFO=1) or disabled (HFO=0).

When the Handfree function is enable (HFO=1), after OFF-HOOK action, it can reset Handfree

function and HFO pin return to "low" state.

Serial data output pin.

NMOS open drain output structure.

When there is a valid entry on keyboard, this pin will output a serial data.

This serial data is designed to drive LCD driver to display dialing number on LCD screen or drive

voice synthesizer to announce dialing number to speaker.

Key tone output pin for key pad input. The key tone duration is the same as the key pressed time.

No matter at Tone mode or pulse mode.

Inverter output structure.

HFI

HFO

SDO

KT

FUNCTION DESCRIPTION

Keyboard Operation

Symbol definitions:

a).

↑

: OFF-HOOK or enable Hand Free function.

b).

↓

: ON-HOOK or disable Hand Free function.

c).

: Input level from low to high.

d).

: Input level from high to low.

e). D

1

.....D

n

: Digit key; 1,2,3,4,5,6,7,8,9,0,*,# (C

1

.....C

n

is same as D

1

.....D

n

).

f). D

P1

... D

Pn

: Pulse digit ; 1,2,3,4,5,6,7,8,9,0, (C

P1

... C

Pn

is same as D

P1

... D

Pn

).

g). D

t1

....D

tn

: Tone digit ; 1,2,3,4,5,6,7,8,9,0,*, # (C

t1

....C

tn

is same as D

t1

....D

tn

).

h). t

F

: Flash time.

i). t

P

: Pause time.

j). t

PT

: Pulse to Tone wait time.

k). t

FP

: Pause time for flash.

l). t

RP

: Pause time for redial.

m). LNB

: Last number redial buffer.

* This specification are subject to be changed without notice.

10.1.1997

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