EM91450 SERIES
TONE/PULSE DIALER WITH LCD INTERFACE
AND I.P.P. DETECT FUNCTION
• 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
EM91450 series. To prevent the unavoidable long distance call, then EM91450 inhibits the key entry during
Tdly.
Operating flow chart
HF
(7)
IPP State
=Hi
(1)
XMUTE
XMUTE=Lo
HKS=Lo
HF
HKS=Lo
On-hook State
HKS=Hi
(2)
HF
(4)
On-hook
Hand-free State
HKS=Lo
Off-hook State
HF
HF
HKS=Hi
(3)
HD
Off-hook
Hand-free State
HD
HF
HD
HF
(6)
On-hook
(5)
Off-hook
Hold-line State
HD
HD
HKS=Hi
HKS=Lo
Hold-line State
<Note> : HF = Handfree
HD = Hold
Truth table
Pin level
Operating state
Input
I/O
Output
HKS
H
L
XMUTE
H/F
PO
F
F
HFO
L
L
HDO
L
L
DTMF
(1) On-hook, idle state
(2) Off-hook line
-
-
H/F
(3) Off-hook, HF line
(4) On-hook, HF line
(5) Off-hook, HD line
(6) On-hook, HD line
(7) IPP state
L
H
L
H
H/F
H/F
L/L
L/L
F
F
F
F
H
H
L
L
L
L
H
H
-
-
-
-
H
L/L
F
H
H
active
Note : F=floating (high impedance); H=logic "High"; L=logic "Low" level.
XMUTE are I/O port, so Input will effect state situation change, and which state dialer stay will
effect output level.
* This specification are subject to be changed without notice.
2.10.1999
7
ELAN [ ELAN MICROELECTRONICS CORP ]
