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I am looking for such IC's which shall be common and cheap. Any Ideas?
it can be found at the following URL. Please do not put any files that are freely available and upload them :x p2001/dtmf_dialer.pdf S :P KRAT
I want to record the dialed numbers from a phone line to a microcontroller.I know about dtmf receiver IC and problem is what is the interface between the dtmf receiver IC and the phone line(not phone) without using any transformer. Can you please advise me? Thanks
I advise to look the modems CMLmicro: CMX624, CMX644A, CMX867, CMX868 I with them work and I have no problems.
hi .. from concept of gsm the gsm voice channel is designed to carry voice. The codec is optimized for human voice. The transfer characteristic is very poor for data transmission. Even 1k2 is almost impossible to modulate to voice channel with reasonable ber. If you want small amount you can use dtmf sequences with suitable hardware. Be carefull
There is no problems with dtmf decoding on 1-2 MIPS micro. Please look on my app note AN2107 from Cypress Micro ( ) and you can easily to port on own CPU in hours. I test this for many weeks, so it works fine
lol what you need is a relay activate the line a selector to select the digits normaly on the toy and or gate {for a clock 1khz to gate the selector and matrix} and some diodes one for the phone line to modulate it the others for the diode matrix you also need a cheep kids telephone it hasa dtmf chip in it and 8 handy
MITEL has changed its name. It is now called ZARLINK. The datasheet you are looking for is probably this one. OkGuy
May This link can help you, sir. :)
Please help me about using AT89C51 to program transceiver dtmf 8880C,and i wonder what pin Clock use Thanks
8880C is Integrated dtmf Transceiver with Motorola compatible processor interface. You should switch to 8888C Integrated dtmf Transceiver with Intel Micro Interface. The pin Φ2 is replaced by /RD. The Read and Write signals that are combined into one single input (R/W) in 8880C, has been splited on two pins /RD and /WR on 8888C Or even b
hello. i m facing problem in cli detection, whether it is in fsk mode or dtmf mode & also suggest me some method or tools by which i can detect as well as decode cli in both dtmf and fsk mode. is the same ic ment for dtmf detection can decode fsk as well. waiting for a positive reply. thanks (...)
Maybe you can post your code here, might be a problem with a misconfigured I/O pin of your pic. Also post which pin of the dtmf chip is connected to which pin of your pic. best regards
From the MC45 datasheet I don´t see any description if it is possible to dial a number by sending dtmf tones through audio channel or not... Someone can confirm this?
Hi, Look at MT8870 from Zarlink look also this old topic = t
Holly!!! Back to the sixties? Dial 1 if fire Dial 2 if intruder Dial... Or wait for operator????? Today at the cost of $1 per 2Mbytes i think gprs is the go. And no wiring needed altogether.... How much costs the telephone minute anyway? ...
Take a look at this application note from rensas: I used it to implement dtmf generation on a PIC but I think you can only do it easily using hardware PWM (which I used on a 16F628). best regards
Here is my proram dtmf detetor using sound card, the audio sinal input is mic_in or line_in, enjoy :roll:
dtmf is like a voice. If you do not use a mic to detect this sounds you do not need a dtmf receiver , if you want to communicate with cell phone by data cable or IRDA , it is just a digital communication. dtmf has nothnig to do with it.
A couple of chips that might be useful: A source of schematics for ideas:
i use ht9200 dtmf generator and cd8870 as decoder.
Hi This is a complicted project since you will need to decode dtmf (use 8870 to do that ) read it into a ucontroller and have the ucontroller generate Bel202 protocol data using the uart , Send the data to XR2206 FSK modulator and you got a sulation ! All the best Bobi
does anyone hav the algorithm or Blackfin code for dtmf to FSK Caller ID conversion
Hi, Comparing the two datasheets, zarlink use a 4.7meg resistor between OSC1 pin and Vss. Carlifornia Micro Device do not. Meabe the oscillator of the chip do not start. If you dont have this resistor on your board, try to add it.
Hi, Here is what you are looking for: The code is for PIC16C54 and its not that diffrent then the PIC16F84, but you will need to do some code cahnge... Good luck. Bro , That's code using what's compiler ? and how to compile ? i already try using parallax asm compiling b
@sweet_nth, everything can be done using a microcontroller and a PWM output :-) See my post here for details: best regards
UMC is not more available, you can use the universal MT8880 , encoder & decoder, in the net you can find many source code for drive it
Better search Edaboard first before asking question, I had post same problem just last month.
krishna3d, look here (and use the search function before opening a new thread next time): best regards
There have a limited bandwidth allocated for the voice band by telephone company. So, if we use square wave, it will cause some misdetection.
i wanna to learn dtmf i am zero in that field could any body help me
you can use mt8880 for DTFM out-in in the caller id data from bs incomming before first ring in dtfm format. but for caller id in FSK-DTFM MT8843 is the best. or PCD3316
i think you will ring detector to each line and the output of ring detector open the line to the caller ID cit you may need analog switches such as 4053 to make this multiplexing
There is a well designed and simple to build dtmf intercom circuit using telephone handsets shown at: The details and parts list for the dtmf portion are at:
i want to use MT8880 dtmf Transiever please tell me about it can i short the in and out pins of it to use it as both transmitter and reciever? any site on which i can get more data of it i have studdied the data sheet of this thanks
Easy. Use the components from an old 2500-type touchtone pad. Two inductors, a couple of transistors,. and a few caps and resistors.
shows the frequencies. Note that there are two frequency bands that are less than an octave wide. Also no frequency is a harmonic of another frequency. What is usually done is the signal is separated by a high and a low pass filter. Then the frequency in each output is measured.
I making an autodialer for handsfree operation. I could dial the number using dtmf generated by a microcontroller. This part works fine. I used a regular microphone from a phone handset for testing. I coupled it to the line using a 600 ohm transformer and it seems ok. But how can I combine : microphone, handsfree speaker and dtmf signal all t
if you want use a 8051 to generataaions dtmf I have the diagrama schematic and source file in assembler, if you want tell me I post here
I have it but use a microcontroller 8051 to geneton, if you want I post schematic and software in assembler tell me and i post it
Go to: It is 8051-base single board computer with a lot of peripherials including EPROM, LCD display, ...... Regards, IanP
hi all I want to work on MT8880 dtmf encoder/decoder please tell me about the easy way to use it at least as encoder only. its data sheet is not easy enough to make it use easily i can work on AT89Cxx family by using assambly language. Thanks in advance
Hi SI-LABS have an app not for the 8051Fxxx for decoding dtmf signal all written in C language All the best Bobi About what application you talk? AN122 - here there is only outputs dtmf tones! Added after 20 minutes: Hi; you als
Dear Friends Currently I am working on a Intruder Alarm system project with auto-dialer facility. In our system we dial the remote user during security break-up, also we are giving facility to control the system using dtmf keys from the remote side. Now we are facing some problems: (1) Initially we designed the hardware, then we wrote the s
Go to the mcirochip site and look for a very old appliation note talking about dtmf Coudl help you in creating something. ?Buena suerte!
Use MT88L85 for dtmf coder/decoder and a simple FM transceiver to make wireless
The MATLAB Signal Processing Toolbox includes a dtmf generation/detection demo. Click Help, Demos, Toolboxes, Signal Processing, Transforms, Dual-Tone Multi-Frequency (dtmf) Signal Detection. Or search MathWorks web site, and you'll find the same demo:
See this link, might be a useful....although they are not using dtmf Good luck
How to realize dtmf signal by two sin signals. dtmf signal is combined by two sin signals(low frequency and high frequency). Thanks to your any idear.


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