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therealpiguy
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Joined: Wed Feb 07, 2018 7:57 pm

Telephone and Raspberry Pi

Wed Feb 07, 2018 8:26 pm

Hello everyone,i want to build this project but i don't know if it's possible to do with the raspberrypi, i want to build a speaker,microphone that can record telephone calls. I currently use a voip, however even If I hard wire a POTS into the pi.

I want to record telephone phone calls to help with hearing impaired.

Sincere thanks-

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penguintutor
Posts: 376
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Location: UK
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Re: Telephone and Raspberry Pi

Fri Feb 09, 2018 10:49 am

First a disclaimer - always be legal!
You may need to check what the law says about recording calls. It sounds like you should be okay with what you are planning, but even if recording your own calls you may have a legal obligation to warn others when you are recording the calls.

Whether it's possible to tap into a voip call would depend upon whether it uses encryption. You can monitor network traffic using tcpdump or wireshark, but that would then need to be converted into an audio signal. If it's encrypted then that is practically impossible to decode (unless you have the resources of a government agency).
But if you are using a computer for the voip application then you could record the audio output that is going to the headset instead.

Tapping a regular POTS line can be done with a telephone recorder / line adapter. You can search for one of those, but you may need to check for appropriate protection against electrical spikes. These normally provide the audio on a 3.5mm jack plug which needs an adapter so that it can work with the Raspberry Pi (eg. a USB sound adapter).

An alternative is just to put a small microphone near the phone and connect that through a USB sound adapter into a Raspberry Pi (although that may result in too much background noise for what you need this for).

Once you have the audio then you just need something to record it. You can do that manually through an application such as Audacity, or look at automating it using PyAudio http://people.csail.mit.edu/hubert/pyaudio/ or similar.

i486
Posts: 172
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Location: BG

Re: Telephone and Raspberry Pi

Fri Feb 09, 2018 12:17 pm

penguintutor wrote:
Fri Feb 09, 2018 10:49 am
First a disclaimer - always be legal!
You may need to check what the law says about recording calls. It sounds like you should be okay with what you are planning, but even if recording your own calls you may have a legal obligation to warn others when you are recording the calls.
I have voice recorder (SONY) which can be connected to phone and record calls. Do you think it is illegal? Or you think there is sound to inform remote person? No, there is no signal and I don't think the recorder is illegal. Maybe you worry about things that are not your job.

hippy
Posts: 5350
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Location: UK

Re: Telephone and Raspberry Pi

Fri Feb 09, 2018 12:21 pm

i486 wrote:
Fri Feb 09, 2018 12:17 pm
I have voice recorder (SONY) which can be connected to phone and record calls. Do you think it is illegal? Or you think there is sound to inform remote person? No, there is no signal and I don't think the recorder is illegal. Maybe you worry about things that are not your job.
A device itself may not be illegal to own but it may be illegal to use or use in certain ways. One would have to check what the local laws and regulations were.

And I expect we'll now have a flurry of posts saying that, even if it is illegal, there's nothing to stop you acting illegally, that no one will care if you do act illegally, that you likely won't get caught if you do.

achrn
Posts: 371
Joined: Wed Feb 13, 2013 1:22 pm

Re: Telephone and Raspberry Pi

Fri Feb 09, 2018 2:16 pm

i486 wrote:
Fri Feb 09, 2018 12:17 pm
I have voice recorder (SONY) which can be connected to phone and record calls. Do you think it is illegal? Or you think there is sound to inform remote person? No, there is no signal and I don't think the recorder is illegal. Maybe you worry about things that are not your job.
I have no idea whether it's illegal or not in your jurisdiction, but since the OP didn't post where he or she is, and therefore we don't know the legal jurisdiction in which they are operating, the observation that you believe your telephone recorder is not illegal is completely irrelevant to the observation that in some jurisdictions some recording of conversations is not legal.

For example, in Germany recording telephone discussions without the explicit consent of all the parties is a criminal offence under section 201 of the German Criminal Code: https://www.gesetze-im-internet.de/engl ... html#p1730

Pithagoros
Posts: 580
Joined: Wed Nov 12, 2014 8:16 pm

Re: Telephone and Raspberry Pi

Fri Feb 09, 2018 2:52 pm

Recording calls where one party is the recorder and for private use is not illegal in the UK, not even if it is done without the knowledge of the other party.
But for business purposes, or to use the recordings for any purpose where a 3rd party will be involved then the call must have been recorded with the knowledge and consent of the other party.

There are plenty of reasons to record a call for your own use, in order to ensure that you have got all the information, somebody I know who has short term memory problems records all her calls for this reason. And as the OP says, for the hearing impaired (regarding the hearing impaired asking somebody to transcribe the call might be a grey area but common sense puts it on the lawful side).

Call recorder used to be standard on Nokia phones, now I think the only HMD Nokia that does it is the Nokia 130. For smartphones there are plenty of downloadable apps.

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