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Help with setting up a modem card

Anonymoose

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Feb 19, 2024
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Heyo,
I have a Practical Peripherals PM9600 (V.32/V.42bis) and I’m not entirely sure how to use it? I can’t find much about it on the internet and don’t know what settings to choose for it. I’ve seen many different modem init strings and the default settings of baud rate:9600, data bit:8, stop bit:1, and parity:none still give me a BUSY signal after calling any BBS. Then again, there could be other things wrong, but I’m not sure. I’m using Procomm 2.4.3 if that helps out anyone. Thanks
 
Have you checked if the BBS number is accurate? Called with some other phone to make sure it isn't actually tied up with another call? Could you post the identity of one of the BBSes being tried? Someone could probably double check for the proper settings. I could take a stab at it but it has been about 30 years since I last used Procomm Plus to access a BBS.
 
The magic behind these older ISA modems is that they appear to the computer as a COM port. No drivers. Just configure it as the next available COM port, point your software at that port and there you go.

I would avoid the init strings for the moment and just try what ATDT [BBS phone number] <enter> and see what it does.
 
I tried a few more numbers, some gave me a busy signal and some said the call could not be completed, please try again. The card does seem to work though. I tried calling one of the numbers (Keep BBS, 503-852-3170) on a landline phone and the dial up beeps and boops were there.
 
Just try to call a number you can hear ringing, like your mobile phone, to make sure the call happens and to help troubleshoot in case it doesn't.
 
I tried calling my personal phone number from the card and it still gave me the BUSY message.
 
Practical Peripherals was founded in 1981, purchased by Hayes Microcomputer Products in 1989, then in 1991 Keating Technologies became the exclusive Canadian Representative for these products. They have an email address for technical support. I am not sure if there is a US Representative or if emailing Keating will be helpful or not.


It sounds like the modem is incorrectly dialing numbers. Could the DTMF tone frequencies be wrong? A DTMF decoder could show what is actually being dialed. If it follows the full Hayes command set, there could be some settings in the modem S registers throwing it off, although you would think there would be a way to reset it to defaults.


Then what about this? - https://archive.org/details/ref-manual-for-practical-peripherals-modems/mode/2up

or https://archive.org/details/PracticalPeripheralsDriverAndUtilitiesOnlineModemUsersReference1996
 
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IMG_4773.jpegnot sure if this may help, but here are the settings it’s giving me (I haven’t changed any of them)
 
In "1) Modem Init String" - try changing S11=55 to S11=95 - This is the duration in milliseconds of the DTMF tones. The default setting is 95 - perhaps 55 is too short of a duration.
 
No dice. Would a video help? I could write down everything that happens but that would be a lot
 
I don't think a video would help. It could be that you have a hardware defect. Perhaps you could listen on the telephone line while it is dialing (a signal tracer or small audio amplifier should work without triggering the line to be off-hook and use a series capacitor on both leads to feed the audio input to prevent the phone line DC voltage from getting to the amplifier) and see if it sounds like it is doing what it is supposed to. You could even try dialing with fewer digits. It won't be a valid phone number, but it may be easier to count the tones to match the number of digits dialed. Measuring the frequencies of the DTMF tones would be even better (two tones per digit). There must be something wrong with that as dialing with DTMF tones is fairly simple. Another thing you could do is measure the voltage of the phone line to make sure it is being held off-hook while dialing. It should be somewhere around 48V on-hook and drop to somewhere around 6V while off-hook and not jump around too much while dialing. I doubt that the modem is polarity sensitive, but you can even try reversing the red and green wires of the phone line. If it is polarity sensitive, I would think a hardware defect would be the likely reason.
 
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It can be
I tried a few more numbers, some gave me a busy signal and some said the call could not be completed, please try again. The card does seem to work though. I tried calling one of the numbers (Keep BBS, 503-852-3170) on a landline phone and the dial up beeps and boops were there.

Is the phone line the modem on a POTS line or a VOIP line? Modems don't work well or at all on VOIP lines because of the digital compression corrupting the tones.

It can be hard to know if you have a real POTS line anymore, because telcos have increasingly upgraded their exchange boxes with VOIP and fiber. So you can have a POTS connection to a telephone exchange, but it gets converted to digital farther down the line.

We in the security industry had to start giving customers ultimatums to upgrade their security panels with IP or cell communicators, because as VOIP service started rolling out across the region, older modem only panels would have severe trouble communicating, or would fail entirely. You could dial a panel and sometimes it would connect, but it would almost immediately start having data errors in the communication and disconnect.

I don't think there's a single telco provider in our region anymore that offers a real POTS line. For awhile some offered a "legacy" trunk at astronomical prices, but as equipment wore out or failed, that went away entirely as well.
 
All good answers! I do admit, I know nothing about phone lines and whatnot. I could take a photo of all the cables and boxes in my garage, but that might not help?
 
All good answers! I do admit, I know nothing about phone lines and whatnot. I could take a photo of all the cables and boxes in my garage, but that might not help?

You need to figure out where the phone lines in your house connect to. If they go back to an RJ-11 jack on your internet modem, then you have VOIP service.
 
Were you around back in the days of land lines? If so, do you know how to dial long distance on one? No offence is meant by this question, but there are a lot of young people these days that may have never used a land line. A real land line will probably require you to dial 1 and the area code to dial a phone number outside of your your current area code. If the phone number you're dialing is "local" then you probably do not need a 1 or an area code.

Would a video help?

I think it would.
 
Just (temporarily) turn off the internet modem and see if your dial tone disappears and the phone line appears to be dead.
I unplugged what I assumed to be the modem, an Arris TM1602, and the phone line still worked.

Were you around back in the days of land lines? If so, do you know how to dial long distance on one? No offence is meant by this question, but there are a lot of young people these days that may have never used a land line. A real land line will probably require you to dial 1 and the area code to dial a phone number outside of your your current area code. If the phone number you're dialing is "local" then you probably do not need a 1 or an area code.



I think it would.
No offense taken! I was born in 2002, so I do know of dialing +1 beforehand.

The video is a bit large in size, so if it’s okay, I’ve made a wetransfer link with it.
 
In the video, I did not hear a brief dial tone just before it started dialing. I am not sure if there is a delay that would cause the dial tone to not be heard, but I think that it needs to be verified.
If the dial tone should be there, but isn't, it could be caused by a defective cable (between the computer and phone jack) or if the modem is defective and does not place enough load on the phone line to go off-hook and trigger the dial tone.

From the Wikipedia page that shows all of the modem commands, you could type the command in the terminal "ATH1" to take the phone line off-hook and verify that you can hear the dial tone. The command "ATH0" should hang up the phone after that.

There are other commands that could be played with such as "Lx" (x = digit) for speaker volume, and "Z" for modem reset, etc. Please study that page and experiment to see what additional clues that you can get.

 
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