EM91450 SERIES
TONE/PULSE DIALER WITH LCD INTERFACE
AND I.P.P. DETECT FUNCTION
I.P.P. DETECT function
The EM91450 series provide the I.P.P. function to pretect illegal connect. I.P.P means Illegal Parallel Phone
Detect. I.P.P. function depend on XMUTE pin and HKS, HF status. When in the ON-HOOK condition and HF
turn off, the XMUTE pin will be a Input pin to detect the voltage lever, otherwises, the XMUTE pin will be a
normally output pin use for control speech network. When I.P.P. function detect. XMUTE pin at "low" status (In
On-Hook and HF turn OFF state), EM91450 will turn on HF and send alarm signal to telephone line. In alarm
duration DTMF pin will continue sending "#","8" "8" signal. The DTMF signal will interfere the illegal user until
the illegal user hang up the phone and the XMUTE pin detect "high" again. The telephone circuit design can allow
the legal internal connect user. (see I.P.P Application CIRCUIT).
* This specification are subject to be changed without notice.
2.10.1999 10
ELAN [ ELAN MICROELECTRONICS CORP ]
