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* This specification are subject to be changed without notice.

4.28.1999

EM91850

TONE/PULSE DIALER WITH HF, HD, REDIAL

AND VOLUME CONTROL FUNCTION

Preliminary

Volume add function

EM91850 provide Volume Add function to control the speech network for adding the receiving volume. Except

idle On-Hook state, Volume add function will working effect no matter what state is. Volume add function are

toggle structure. Every time touch VA key will inverter the VAO pin condition ( H

→L→H→L→.....). So Volume

add will active or release each time keying VA. If and only if, when dialer back to the idle On_Hook state then

the Volume add function will force to release. This solution protect the user will not be hurt by loud volume.

Although Volume add state will not change by Off_Hook or HF operation but if dialer are in HF mode then

Volume add outpout (VAO) will be inhibited.

Noted : Except dialer back to idle state, any other operate will not reset volume add situation ( include HD,

HF , Flash ..... , and so on ). So volume add situation will be hold until dialer back to idle.