EM91440 Ver la hoja de datos (PDF) - ELAN Microelectronics
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EM91440 Datasheet PDF : 24 Pages
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EM91440 SERIES
TONE/PULSE SWITCHABLE DIALER WITH LCD INTERFACE
AND DUAL-TONE MELODY GENERATOR
Flash (F) key operation
The Flash (F) key is designed to break telephone line temporarily. After F key is depressed, this dialer will send
a flash signal to break line 600 ms, 300 ms, 100 ms or 80 ms; as ROW3 and ROW4 selection.
Handfree (HF) function
The handfree function is designed to support on-hook dialing and loudspeaker application which can be turn “on”
or “off” with falling edge signal from HFI pin. During handfree function is executed, the HFO pin is switched
to “high”. Otherwise the HFO pin stays “low” level. One of the following operations can turn off Handfree
function (HFO pin return to “Low”).
• On-off hook once.
• Trigger HFI pin with falling edge signal.
• Turn on Hold (HD) function. (HDO pin switched to “High”)
Hold (HD) function
The Hold function is designed to stop conversation temporarily. In off-hook state (or HF function is turned on),
to press HD key on the keyboard, the Hold function can be turned “on” (HDO pin switched to “High”). One of
the following operations can turn off Hold function (HDO pin switched to “Low”).
• On-off hook once.
•To press HD key over 280 ms.
• 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
EM91440 series. To prevent the unavoidable long distance call, then EM91440 inhibits the key entry during
Tdly.
* This specification are subject to be changed without notice.
10.1.1997 7
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