Help with setting up a modem card

[bburley]

You could also try changing "X1" in your init string to "X2" or "X4" - See notes on Wikipedia page.

 

[jafir]

I heard the dialtone, but sounded like it turned into a busy almost instantly, while the number was still being dialed.

 

[bburley]

I heard the dialtone, but sounded like it turned into a busy almost instantly, while the number was still being dialed.

Then it sounds like the DTMF tones used for dialing are not correct and triggering the busy response. Either wrong numbers are being sent or the DTMF tones are incorrect frequencies or something like that.
You will need to make a WAV file recording of the tones being sent, then submit it to one of the online DTMF decoders or a downloaded DTMF decoder to see what is actually being sent.

(Took me a minute to realize that this is not the author of this thread )

 

[bburley]

If you are unsure how to check if the phone line voltages are reasonable, here is a short video explaining how -

Your modem should have a similar effect as the telephone for the on-hook and off-hook voltages.

 

[Maikudou]

I definitely hear the line tone before 3rd or 4th dtmf tone made it busy.

Silly question: you did try that number by usual phone and got through to the modem on the other side, right? idk maybe long-distance calls are disabled or something?

Also I don't know how it works in US, I used to add "+" before the number to get to long distance, it would be "+1 xxx xxxx xxx" if I wanted to call to the US 1 being country code Probably it is irrelevant.

 

[bburley]

It would be simpler to test local numbers first, like the user's cell phone.

 

[bburley]

I heard the dialtone, but sounded like it turned into a busy almost instantly, while the number was still being dialed.

I do hear it after turning the volume up. Now I wonder if it isn't abnormally low level. X2 or X4 in the init string should be able to confirm if the modem recognizes the dial tone.

 

[Anonymoose]

whoops, I didn’t realize there was a command to turn the volume up. I’ve done so and recorded the result. Unfortunately, X2 and X4 give the same results of dialing, displaying “BUSY”, pausing, and trying again. I tried dialing my personal phone without the +1, and it does the same thing too. As for the landline voltages, I don’t have a multimeter at the moment but I can get one sometime.

 

[jafir]

What happens if you just open the terminal and try to dial manually, just by typing atdt and the phone number? Maybe the init strings you are using are messing things up because they are not compatible with the modem.

It’s frustrating because I no longer have a land line of any sort to “play along” and it’s been so many years since I’ve messed with dialing BBS that it’s hard to remember the exact commands, etc.

Getting older sucks. Also get off my lawn.

 

[bburley]

So this is what gets decoded. Adjusting the sensitivity threshold is tricky probably because it is not a clean recording. If the decoded number is correct, then the issue starts to look like the phone service does not like dialing long distance or the tone levels or background hum or noise could be issues. At this point you likely need some test equipment (an oscilloscope would be good) and the ability to wire up test setups to be able to measure signal levels and you need to investigate the phone service that is being provided and obtain the specifications for signal levels and parameters that are expected. If doing those thing are not easy, then obtain another modem to try, or try your current modem on someone else's phone line.

DTMF Decoder

 

[bburley]

I found the phone number in your first video and the phone numbers are close but do not match.
Possibilities;
1) The modem is defective and does not generate clean tones.
2) The modem is polarity sensitive (reverse red and green wires of phone line to test)
3) The recorded audio is poor quality and introduces noise and distortion.

For item 3 - I would try to hook a tape recorder (or the microphone or line input of a computer audio card - does not have to be the same computer) and try to make a better recording. This may be tricky. You will need a phone cable coming from the modem that has wires that you can connect to. You will need some basic electronics knowledge to get this wired up. If the modem depends on phone line DC voltages to work properly, you will need to know how to properly set it up to trick the modem.

And there is always the easier option of getting another modem for a comparison test.

 

[Anonymoose]

What happens if you just open the terminal and try to dial manually, just by typing atdt and the phone number? Maybe the init strings you are using are messing things up because they are not compatible with the modem.

It’s frustrating because I no longer have a land line of any sort to “play along” and it’s been so many years since I’ve messed with dialing BBS that it’s hard to remember the exact commands, etc.

Getting older sucks. Also get off my lawn.

That doesn’t work either. Either BUSY or NO CARRIER