EM91401 SERIES
TONE/PULSE SWITCHABLE DIALER WITH LCD INTERFACE
AND DUAL-TONE MELODY GENERATOR
• 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.
Operating flow chart
HKS=Lo
1
HF
HKS=Hi
HF
On-hook state
2
4
HKS=Lo
On-hook
Hand-free state
Off-Hook state
3
HKS=Hi
HF
HF
HD
HD
HF
HD
Off-Hook
Hand-free state
HD
6
HF
5
HD
ON-Hook
Off-Hook
Hold-line state
Hold-line state
HKS=Hi
Off-Hook
Hold-free state
HKS=Lo
<Note> : HF = Handfree
HD = Hold
Truth table
Operating state
Input/Output pin level
HKS
H
L
L
H
PO
F
F
F
F
XMUTE
HFO
L
L
H
HDO
L
L
L
L
(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
F
F
F
F
L
L
H
L
H
F
F
L
L
H
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.
* This specification are subject to be changed without notice.
10.1.1997
7
ELAN [ ELAN MICROELECTRONICS CORP ]
