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Digital interface for a landline based telephone system

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0x34

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PROJECT: Building a device, which interfaces with a Laptop. The laptop will communicate with a Microcontroller (via RS232), which is in an external "box." The controller in the box needs to interface with an IC that incorporates these abilities:

· Capable of analog phone conversation (amplification - 2 way)
· Has DTMF capability, via uC input (8 bit bus)
· Interfaces to 8 bit uC
· Has status lines (line detect – voice detect – busy detect etc…)
· Is as stand-alone as possible.

Anyone heard of or know where I might find a IC like this??? :?:
 

kinjalgp

Active Member
What you are searching for is a Modem IC. Either you can use external modem which is capacble of doing all the tasks you mentioned or use any of the avilable MODEM ICs.
 

0x34

New Member
It's a specific device that I'm building. While a FAX/Voice/Modem does some of the tings I need, It is inadiquate for my purposes (which do NOT involve any DATA communications). What I need is a good IC to start from. Any Ideas?
 

kinjalgp

Active Member
Yes ofcourse, it does involve data communications.
 

0x34

New Member
Let me rephrase that... It doesn't require any data telecommunications (referring to the telephony end of the unit). Of course there will be digital communication between the IC, sub controller and main windows based PC, however the information over the phone line will be all analog (voice).
 

Sebi

Active Member
The word "voice" in data/fax/voice-modem say: this type of modem have a microphone and speaker in and out for voice transfer in 300....3200Hz band as a normal phone...
As i know: no existiert a standalone IC for this function.
 

tdb

New Member
I'm not aware of an IC that would do both audio I/O and receive DTMF. But it doesn't make sense to use RS-232 to send/receive audio via your telephone line. Instead, just use your speaker-out and line-in connections on your soundboard (or a second sound-board). Use the microcontroller and a DTMF transceiver to send/receive DTMF signals. Then, put a switch on the telephone line to determine which to signal to use (i.e. audio or DTMF). It's basically just how a regular telephone works. For that matter, maybe you could canabalize an old one to make it do what you need. Also, check out this site for circuit examples and you may get some ideas:

http://www.discovercircuits.com/T/telephone.htm
 
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