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Dial up modem

Posted: Fri Nov 22, 2013 4:13 pm
by Hammond7372
Anyone know of a dial up modem which will work with the Pi ? :)

Re: Dial up modem

Posted: Fri Nov 22, 2013 4:39 pm
by FLYFISH TECHNOLOGIES
Hi,
Hammond7372 wrote:Anyone know of a dial up modem which will work with the Pi ? :)
What interface type do you have in mind ?
Every external "AT-command" modem with RS-232 should work.


Best regards, Ivan Zilic.

Re: Dial up modem

Posted: Fri Nov 22, 2013 5:36 pm
by Lob0426
I found this under a search for dial up Linux modems
http://www.usr.com/products/modem/modem ... ku=USR5637

Re: Dial up modem

Posted: Fri Nov 22, 2013 8:33 pm
by Hammond7372
I just want to be able to make phone calls with the modem, would I be able to program it with a simple programming language ?

Re: Dial up modem

Posted: Fri Nov 22, 2013 8:50 pm
by DougieLawson
Hammond7372 wrote:I just want to be able to make phone calls with the modem, would I be able to program it with a simple programming language ?
The programming is easy. Almost all modems work on a set of HAYES commands
AT
AT +++
AT DT 01234 56789

If you can hookup a mobile/cell/handy phone as a modem it will react to those HAYES commands.

The old hardware we used to use in the 1980s/1990s was a RS232 DCE. The computer acting as an RS232 DTE. The program for simply connecting to a simple modem was stty.

It's probably more than ten years since I used any modem with any computer.

Re: Dial up modem

Posted: Fri Nov 22, 2013 8:52 pm
by FLYFISH TECHNOLOGIES
Hi,
Hammond7372 wrote:I just want to be able to make phone calls with the modem
Hmm... define "making phone calls"... you dial the number, phone rings, then what ? What is the "setup" on the other side you're dialing to ?
Hammond7372 wrote:would I be able to program it with a simple programming language ?
Modem actions can be programmed/controlled with various programming languages.


Best regards, Ivan Zilic.

Re: Dial up modem

Posted: Fri Nov 22, 2013 8:59 pm
by DeeJay
Two replies here have referred to modems that use rs232. Be aware that the RPi does not have an rs232 serial interface - an external adaptor or additional components will be needed to convert a usb port or some gpio pins before you can successfully connect such a device.

Re: Dial up modem

Posted: Fri Nov 22, 2013 9:16 pm
by MoosePi

Re: Dial up modem

Posted: Fri Aug 22, 2014 1:47 pm
by w1qf
I have a Raspbi B+ running great, and a US Robotics USR5637 modem,
Gnome-ppp and WVDial are installed and can dial out on a POTS phone line.
All I need to do is send a WAV or MP3 voice message out, once the called line (my own fone) picks up.
This is not (repeat, NOT) voice-over-internet. There ain't no internet in this setup.
It's hard to believe no one has ever done this, and I don't want to 're-invent the wheel'.

Any takers?

Regards, Terry

Re: Dial up modem

Posted: Thu Dec 11, 2014 3:57 am
by crossoft
Hi Terry,

I'm trying to do something I think much simpler, and it sounds like you have that part figured out ... I've got an analog phone line (two pair) that I want, using a RPi (and presumably modem) to get a dial tone, and dial a number; when it connects, put the output to a speaker (and input a microphone), and is able to send hang up commands to the modem type device and also listen for touch tones received. It would be put into the physical shell of a call box at a gate entry, to connect would-be visitors to the station via conventional phone.

I figured it was possible with an RPi but don't know where to begin. Any advice on that would be really appreciated! (And, sorry I'm no help in what you're trying to do, although I agree, this problem has to have been solved elsewhere, somehow)

Christopher

Re: Dial up modem

Posted: Mon Jan 18, 2016 4:14 pm
by mordormx
I have the same requirement, any advice?

Re: Dial up modem

Posted: Mon Jan 18, 2016 4:49 pm
by rurwin
I don't believe there is a good answer. There does not appear to be a standard command to enable the microphone; the noise sent is always generated by the modem. If you can find a modem that provides such a feature, and they may be out there, all well and good, but it will be specific to that one modem.

Otherwise I think you will need to either bridge to VOIP or use a GSM modem -- those probably can set up phone calls. Here's a link I found for VOIP, I don't know if it does what you need (tl;dr) http://www.aoakley.com/articles/2008-01-08.php

Re: Dial up modem

Posted: Mon Jan 18, 2016 5:20 pm
by stderr
mordormx wrote:I have the same requirement, any advice?
While you will have to deal with the fact that RS232 is now "RS232" with various voltage limitations, once you get the modem to dial out, if you just need to be on the line, just use a regular POTS phone hooked up to the line. If it is off hook, just have the modem dial the number. If you are wired through the modem, most modems will let you use that to hang up the line or you could sense that hang up in the same way you did the off hook.

Re: Dial up modem

Posted: Mon Jan 18, 2016 7:03 pm
by hippy
There are quite a few USB POTS / FAX Modems out there. One with a telephone jack should be able to switch the exchange line to the phone jack, which can probably be replaced by microphone and speaker.