Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

interface telephone line and HT9200A?

Status
Not open for further replies.
X

xxtigerxx

Advanced Member level 1
Joined
Jun 5, 2001
Messages
441
Helped
38
Reputation
76
Reaction score
32
Trophy points
1,308
Location
Greece
Activity points
2,890
ht9200a

i am using the HT9200A for dtmf generator.

does anyone have a interface circuit for the telephone line

because the circuit that i am using does amplyfie the signal so in the telephone line the signal is below 100mV...
this is to small.

THX
 

telephone line interface

Holtek has a suggested circuit on their website. Did you look at that?
**broken link removed**


There's a complete project using a different DTMF chip at:
**broken link removed**
You could substitute the HT9200 into that circuit
 

ht9200 circuit

THX House Cat

I looked at holtek site but the circuit has no isolation.

thx for the other project

do you have any other schematics?

:p
 

how to interface to a phone line

Please any have a circuit using HT9200 and a opto isolated???

I wanna remove a transistor in the up first image and substitute for a CNY-17... to interface with mcu.
The circuit in the mcu generate square wave... I need a sine wave in to the opto CNY-17. And I think about the RC but not works!!!
I have problem too with the "pop-corns"!!!
sorry for bad english.
Thanks
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top