Make phone calls from computer through land line [duplicate]

Question

I have an ADSL line with 20Mbit/s downstream and 1Mbit/s upstream. Is it possible to make voice phone calls in Linux/Windows 7 using my own land line?

I don't want a VOIP software (like skype), nor an external service which requires an account. Just make a call as I make using a phone device, but using a computer connected to landline through a router.

Linux solution is preferred over Windows 7, if it's possible.

I've been searching how to do it, but I just found VOIP solutions (which requires an external service) or using a 56Kbps modem, but nothing about ADSL line.

I've seen this one: Can TP-Link router make phone calls?, but I'm not sure if we both ask same question. For instance, I don't need, simultaneously, data and voice. I could disconnect internet connection, if needed. And this other: Receive and route phone calls through computer, seems to much complicated. I don't need multiple lines.

Thanks.

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EDIT :
I think my question is not duplicated, because is not answered in that post.

If I'm not wrong (correct me if I am), all answers, like asterisk, need a SIP provider, and that's not what I want. I don't want to pay for another provider. I already have a company who provides my land line (and internet).

In other words: I don't want to make calls through internet, I want to make calls from computer using my land line provider. Is that possible?

Answer 1

To access POTS service--yes, that's the technical term--of a phone line, you'd need hardware that could generate and read an audio signal on the phone line. At a minimum, that requires a physical connection to the phone line.

A consumer-grade modem provides an interface for the computer attached to the modem to take the line off-hook and dial a number. The standard modem interface doesn't give the computer any access to actually send or receive audio over the phone line. So, if your PC had a modem, you could plug the line into the modem and use it to dial the phone, but you'd need a separate phone handset connected to the line in order to talk or listen.

Some computers have what are dubbed "winmodems". The modem hardware is simpler and usually consists of a signal processor which gives direct ability to generate or process an audio signal on the line. An OS-specific software driver provides the normal modem interface. If your computer had one of these winmodems, and you plugged the phone line into it, then you could hypothetically have software which could dial the line and send and receive audio. I'm not aware of any hardware standards for this sort of thing, so you'd be dependent on your PC vendor to provide phone software which worked for your PC's winmodem.

But you say the phone line is plugged into an ADSL router, not your PC. So your PC doesn't even have access to the physical phone line; the router does. For this to work, the router would have to contain hardware for accessing the POTS service, including sending and receiving audio. And it would somehow have to expose that interface over the network. And you'd need software on your PC to access the service on the router.

You would have to check your specific router to see if the manufacturer has provided these features. ADSL don't use the POTS capability of a phone line, and they don't emit or read audio signals. So a typical router isn't even going to contain the right hardware to access the POTS service on a phone line. A router manufacturer could hypothetically construct a DSL router with POTS capability, but it'd be a value-added feature and it'd raise the cost of the device.

Answer 2

First, you need a voice or voice/fax 56k landline modem (dirt cheap these days). It will need to be connected to a serial port on your Linux system, and to a filtered (not unfilitered) phone jack in your house or wherever (like a normal phone would). The correct one to use will likely be an external one (most USB and PCI ones are "winmodems" that rely on the driver to anything but physically send/receive audio).

Second ... I can't find any Linux non-SIP/VoIP softphone apps. A project I played with a long time ago called VOCP will act as an answering machine, answering calls, playing a voicemail message, and allowing recording. So all the building blocks are there for making a live PSTN call I would imagine.