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How does a telephone handset work?

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  How does a telephone handset work? Wanderer <wanderer@dialup4less.com> - 2017-12-21 12:04 -0800
    Re: How does a telephone handset work? Don Kuenz <g@crcomp.net> - 2017-12-21 23:33 +0000
    Re: How does a telephone handset work? Jasen Betts <jasen@xnet.co.nz> - 2017-12-22 20:08 +0000
      Re: How does a telephone handset work? Wanderer <wanderer@dialup4less.com> - 2017-12-22 13:49 -0800
        Re: How does a telephone handset work? rickman <gnuarm@gmail.com> - 2017-12-22 18:49 -0500
          Re: How does a telephone handset work? Wanderer <wanderer@dialup4less.com> - 2017-12-22 16:37 -0800
            Re: How does a telephone handset work? rickman <gnuarm@gmail.com> - 2017-12-22 22:45 -0500

#488977 — How does a telephone handset work?

I want to rig up my computer to be a tty/tdd set for the hearing impaired. I found this software.

http://www.dxsoft.com/en/products/calltty

I'm trying to avoid building the circuit.

I was thinking of using of these instead.

https://www.ebay.com/itm/CallTel-RJ9-Jack-to-3-5mm-Dual-Plugs-PC-Card-Y-Training-Adapter-Cord-2-MUTE-Keys/261885051425?hash=item3cf990c221:g:8LQAAOSwPhdVUZfI

These things are designed to connect handsets to the sound card, but I want to connect the sound card to the handset connector on the phone. Does that work? How does the handset communicate with phone?  

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#488994

Wanderer <wanderer@dialup4less.com> wrote:
>
> I want to rig up my computer to be a tty/tdd set for the hearing impaired.
> I found this software.
>
> http://www.dxsoft.com/en/products/calltty
>
> I'm trying to avoid building the circuit.
>
> I was thinking of using of these instead.
>
> https://www.ebay.com/itm/CallTel-RJ9-Jack-to-3-5mm-Dual-Plugs-PC-Card-Y-Training-Adapter-Cord-2-MUTE-Keys/261885051425?hash=item3cf990c221:g:8LQAAOSwPhdVUZfI
>
> These things are designed to connect handsets to the sound card, but I
> want to connect the sound card to the handset connector on the phone.
> Does that work? How does the handset communicate with phone?

https://en.wikipedia.org/wiki/Modular_connector#Handset_wiring

Thank you,

--
Don Kuenz, KB7RPU

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#489061

On 2017-12-21, Wanderer <wanderer@dialup4less.com> wrote:
>
> I want to rig up my computer to be a tty/tdd set for the hearing impaired. I found this software.
>
> http://www.dxsoft.com/en/products/calltty
>
> I'm trying to avoid building the circuit.
>
> I was thinking of using of these instead.
>
> https://www.ebay.com/itm/CallTel-RJ9-Jack-to-3-5mm-Dual-Plugs-PC-Card-Y-Training-Adapter-Cord-2-MUTE-Keys/261885051425?hash=item3cf990c221:g:8LQAAOSwPhdVUZfI
>
> These things are designed to connect handsets to the sound card, but
> I want to connect the sound card to the handset connector on the
> phone. Does that work? How does the handset communicate with phone?    


If you want to be legal, don't. use a voice-capable modem with
apropriate sound drivers. Or use accoustic coupling, tape a speaker to
phone's microphone and an microphone to the phone's speaker.

If you don't think you'll get caught. use isolating transformers in
place of the speaker and microphone of the receiver and connect them
to line-in and line-out on the sound card, you may need to add
resistors to reduce the volume levels.

https://en.wikipedia.org/wiki/Modular_connector#4P4C

-- 
This email has not been checked by half-arsed antivirus software 

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#489068

On Friday, December 22, 2017 at 3:33:24 PM UTC-5, Jasen Betts wrote:

> 
> If you want to be legal, don't. use a voice-capable modem with
> apropriate sound drivers. Or use accoustic coupling, tape a speaker to
> phone's microphone and an microphone to the phone's speaker.
> 

That's what I'm going to try to do. I going to just build a cradle for the handset and go the microphone connected to the speaker route.

I can't believe these overpriced TTY/TDD devices. They look like 1970's teletype machines with an old fashion modem and a calculator display. I want a card I can plug into my computer.

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#489085

Wanderer wrote on 12/22/2017 4:49 PM:
> On Friday, December 22, 2017 at 3:33:24 PM UTC-5, Jasen Betts wrote:
>
>>
>> If you want to be legal, don't. use a voice-capable modem with
>> apropriate sound drivers. Or use accoustic coupling, tape a speaker to
>> phone's microphone and an microphone to the phone's speaker.
>>
>
> That's what I'm going to try to do. I going to just build a cradle for the handset and go the microphone connected to the speaker route.
>
> I can't believe these overpriced TTY/TDD devices. They look like 1970's teletype machines with an old fashion modem and a calculator display. I want a card I can plug into my computer.

Is there a reason why you don't just connect a standard modem to your 
computer?  My understanding is they often support both voice and data 
operations.  Why do you need to reinvent the wheel?  I just saw a 56 kbps 
modem on ebay for $30 plus shipping.  Plug it into the wall, plug it into 
your computer and you are good to go, no?

-- 

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

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#489091

On Friday, December 22, 2017 at 6:49:16 PM UTC-5, rickman wrote:
> Wanderer wrote on 12/22/2017 4:49 PM:
> > On Friday, December 22, 2017 at 3:33:24 PM UTC-5, Jasen Betts wrote:
> >
> >>
> >> If you want to be legal, don't. use a voice-capable modem with
> >> apropriate sound drivers. Or use accoustic coupling, tape a speaker to
> >> phone's microphone and an microphone to the phone's speaker.
> >>
> >
> > That's what I'm going to try to do. I going to just build a cradle for the handset and go the microphone connected to the speaker route.
> >
> > I can't believe these overpriced TTY/TDD devices. They look like 1970's teletype machines with an old fashion modem and a calculator display. I want a card I can plug into my computer.
> 
> Is there a reason why you don't just connect a standard modem to your 
> computer?  My understanding is they often support both voice and data 
> operations.  Why do you need to reinvent the wheel?  I just saw a 56 kbps 
> modem on ebay for $30 plus shipping.  Plug it into the wall, plug it into 
> your computer and you are good to go, no?
> 
> -- 
> 
> Rick C
> 
> Viewed the eclipse at Wintercrest Farms,
> on the centerline of totality since 1998

I've asked the same question but I can't find any tty/tdd software to work over a voice modem and I don't understand why.

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#489112

Wanderer wrote on 12/22/2017 7:37 PM:
> On Friday, December 22, 2017 at 6:49:16 PM UTC-5, rickman wrote:
>> Wanderer wrote on 12/22/2017 4:49 PM:
>>> On Friday, December 22, 2017 at 3:33:24 PM UTC-5, Jasen Betts wrote:
>>>
>>>>
>>>> If you want to be legal, don't. use a voice-capable modem with
>>>> apropriate sound drivers. Or use accoustic coupling, tape a speaker to
>>>> phone's microphone and an microphone to the phone's speaker.
>>>>
>>>
>>> That's what I'm going to try to do. I going to just build a cradle for the handset and go the microphone connected to the speaker route.
>>>
>>> I can't believe these overpriced TTY/TDD devices. They look like 1970's teletype machines with an old fashion modem and a calculator display. I want a card I can plug into my computer.
>>
>> Is there a reason why you don't just connect a standard modem to your
>> computer?  My understanding is they often support both voice and data
>> operations.  Why do you need to reinvent the wheel?  I just saw a 56 kbps
>> modem on ebay for $30 plus shipping.  Plug it into the wall, plug it into
>> your computer and you are good to go, no?
>>
>> --
>>
>> Rick C
>>
>> Viewed the eclipse at Wintercrest Farms,
>> on the centerline of totality since 1998
>
> I've asked the same question but I can't find any tty/tdd software to work over a voice modem and I don't understand why.

That seems crazy.  Maybe they don't realize it doesn't need to be different? 
  It has been a long time since I've worked with modems, but the audio 
interface should work the same as a sound card under windows.  It should 
appear as an audio device.  Obviously there has to be some difference so you 
can take the phone off hook.  I remember when the win modems came out they 
weren't much more than a sound chip and the telephone DAA.

Maybe someone here knows if a built in modem has an interface compatible 
with a sound card?

-- 

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

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