em91401 ELAN Microelectronics Corp, em91401 Datasheet - Page 7

• Manufacturer Part Number: em91401
• Description: Tone/pulse Switchable Dialer With Lcd Interface And Dual-tone Melody Generator
• Manufacturer: ELAN Microelectronics Corp

* This specification are subject to be changed without notice.
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......
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.
Operating flow chart
Truth table
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.
<Note> : HF = Handfree
• Turn on Handfree (HF) function. (HFO pin switched to “High”)
(1) On-hook, idle state
(2) Off-hook line
(3) Off-hook, HF line
(4) On-hook, HF line
(5) Off-hook, HD line
(6) On-hook, HD line
Note : F=floating (high impedance); H=logic “High”; L=logic “Low” level.
Operating state
HD = Hold
Dummy key
HD
Lock number key
ON-Hook
Hold-line state
Off-Hook
Hold-line state
On-hook
Hand-free state
HD
4
6
HF
HF
HKS
H
H
H
L
L
L
HF
HKS=Hi
TONE/PULSE SWITCHABLE DIALER WITH LCD INTERFACE
HKS=Hi
F
F
F
F
F
F
PO
On-hook state
Off-Hook
Hand-free state
HKS=Lo
1
3
HKS=Lo
Input/Output pin level
HD
XMUTE
F
F
F
F
L
L
AND DUAL-TONE MELODY GENERATOR
HF
HKS=Hi
HF
HF
HKS=Lo
Off-Hook state
Off-Hook
Hold-free state
2
5
HFO
HD HD
H
H
L
L
L
L
EM91401 SERIES
HDO
H
L
L
L
L
H
10.1.1997
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