EM91401 SERIES

TONE/PULSE SWITCHABLE DIALER WITH LCD INTERFACE

AND DUAL-TONE MELODY GENERATOR

7

* This specification are subject to be changed without notice.

Preliminary

Preliminary

Preliminary

Preliminary

Preliminary

10.1.1997

Operating flow chart

1

HF

HF

On-hook state

HKS=Hi

HKS=Lo

4

On-hook

Hand-free state

HKS=Lo

2

Off-Hook state

HF

HF

HF

3

Off-Hook

Hand-free state

HKS=Hi

HF

HD

HD HD

HD

HD

6

Off-Hook

Hold-line state

HKS=Hi

HKS=Lo

5

Off-Hook

Hold-free state

<Note> : HF = Handfree

HD = Hold

Truth table

Operating state

Input/Output pin level

HKS

PO

XMUTE

HFO

HDO

(1) On-hook, idle state

H

F

F

L

L

(2) Off-hook line

L

F

F

L

L

(3) Off-hook, HF line

L

F

F

H

L

(4) On-hook, HF line

H

F

F

H

L

(5) Off-hook, HD line

L

F

L

L

H

(6) On-hook, HD line

H

F

L

L

H

Note : F=floating (high impedance); H=logic “High”; L=logic “Low” level.

Music on Hold

EM91401 series built-in a melody generator to generate dual-tone music on DTMF output pin. The music is

designed for telephone line at line holding.

• Turn on Handfree (HF) function. (HFO pin switched to “High”)

Special Note:

A 300 ms delay time (Tdly) at the first Off-Hook or turn on Handfree that is a special designed to avoid a rapid

key entry (dummy number ) in this time duration ,and a long distance call number follows. For example,

Off-Hook , “3” ,............ , “0” ,1,2,3......

Dummy key

Lock number key

The dummy number “3” is not detected by the centered office or PABX ,but the following numbers “0” ,1,2,3...

long distance call can be dialed out normally since the leading number “3” is not the Lock-number defined in

EM91401 series. To prevent the unavoidable long distance call, then EM91401 inhibits the key entry during

Tdly.

ON-Hook

Hold-line state