Dialer problem with a picchip

What are your audio levels at the line? Tom

Well, from what you're saying and what I see on that sight, I would say that some how you have hacked it and not removed the actual rotary pulse dialing code out of it?

Looks suspiciously like it. At first sight I though he was intentially trying to send dial pulses.

Graham

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I am just using the diagram on that web site. That is it, no program no nothing else. Ok that said, I modified the hardware because I am using DTMFout in picbasic that produces the dialing., I just added a max7480 to filter out the noise because the signal get to the audio transformer.

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Meaning ?

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If the CO is detecting DTMF, dial tone will stop.

Some POTS lines won't pass DTMF if T/R are reversed. Levels (too high, often) & distortion can hurt DTMF detection. Digit-on or inter- digit time might be too short; send just 1 digit & see if DT stops.

JM

You might want to post your ACTUAL circuit & ACTUAL program, if you want to get ACTUAL good answers. Posting an example of what it ISN'T, isn't necessarily going to get you what you want.

JM

Maybe you're over driving the line?

"then I also hear the controller dialing..". From the write up, I thought it -was- designed to pulse dial using the relay. No?

Try disconnection the audio feed to the xformer from the chip and let it go through the process. See if then, it is causing the problem. If it does not cause the line to reset, then you know you have an over driving issue.

Also, look at the quality of the signal on the line side using a scope.

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Ok I will make a schematic. I look in my pspice but I dont have anypic chip or the max7480 IC. Anyone know of a program that contains most of the IC s out there? without being a simulation software.

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I got the circuit working now, the odd thing it works only when I put the speaker (9 Ohms) on the transformer, The positive on the positive of the dtmf input and the ground on the phone ground. I guess that means it is not getting enough current in.... ?

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here is the diagram. It do not dial without the 9 Ohm resistor...

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HI,

Here is the diagram. It do not dial without the 9 Oh

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It's very obvious why it don't work as desired.

You have no DC path on the line side to load it down.. On the C connection, remove the cap and 150 ohm R and connect it directly to the xformer.

Remove the 9 ohm R from where it is and if needed connect it across C and D connections to add a load. I don't know what you're using for a Xformer so I don't know what the DC resistance is in the secondary of it how ever, you need to proper DC resistance to bring the line to a normal off hook voltage.

Again, reading a book on the basics would be useful. Characterizing *what exists* and determining an interface should have come first. Like so many folks, you started at the wrong end of the project (like the guy that wanted to use rechargeable batteries to run LEDs but didn't know what the *energy demand* would be because he hadn't even picked a LED).

Meaning putting too many volts onto the line. Have you read the specs for DTMF dialling and know the correct levels ? You'll find them on the data sheets for DTMF dialler chips (if you can still find one).

Graham

What speaker ? You haven't shown a circuit with a speaker AFAICS.

No it's probably the speaker loading the signal level down to an acceptable level.

From memory you only need about 1 V of signal. You'll probably break the PIC if you use it to drive 9 ohm louspeakers.

You seem to be attempting a challenging project for someone with so little basic knowledge. Like building a house on sand foundations.

Graham

Almost certainly your voltage level is wrong initially.

Put a voltage divider between the PIC and the MAX 7480 to reduce the signal level. Try about 20% of the PIC's output.

Graham