* This specification are subject to be changed without notice.

8

4.28.1999

EM91850

TONE/PULSE DIALER WITH HF, HD, REDIAL

AND VOLUME CONTROL FUNCTION

Preliminary

<Note> : HF=Handfree

HD=Hold

(1)

On_Hook

state

(2)

Off_Hook

state

(4)

On_Hook

HF

state

(3)

Off_Hook

HF

(5)

Off_Hook

HD

(6)

On_Hook

HD

HKS=L

HKS=L

HKS=H

HF

HF

HF

HF

HF

HF

HD

HD

HD

HKS=H

HD

HD

HKS=L

HKS=H

OPERATING FLOW CHART

Truth Table :

Operating state

Input / Output pin level

HKS

PO

XMUTE

HFO

HDO

(1)On-hook, idle state

H

Z

L

L

L

(2)Off-hook line

L

Z

L

L

L

(3)Off-hook, HF line

L

Z

L

H

L

(4)On-hook, HF line

H

Z

L

H

L

(5)Off-hook, HD line

L

Z

H

L

H

(6)On-hook, HD line

H

Z

H

L

H

Note : Z= floating (high impedance) ; H= logic "High"; L= logic "Low" level.

@ = To doing R-option