🚀 go-pugleaf

In article <1992Aug31.043725.13428@u.washington.edu> wiml@milton.u.washington.edu (William Lewis) writes:
>From: wiml@milton.u.washington.edu (William Lewis)
>Subject: Re: Mac to Phone connections...
>Date: 31 Aug 92 04:37:25 GMT
>In article <1992Aug27.160630.615@fwi.uva.nl> aroest@fwi.uva.nl (Axello de Roestello) writes:
>>rubin@cis.ohio-state.edu (Daniel Rubin) writes:
>>
>>>Hi all... I want to connect my Mac to my phone.  I am going to connect the
>>>speaker of the Mac to the mic of the phone and the speaker from the phone to
>>>the Mac's mic...
>>
>>>I know that the levels do not match.    ...
>>
>>Don't do it!!!
>>Not only do the levels not match, the phone line can have 60 volts across its 
>>wires and will fry your Mac when it is ringing. 
>
>  To me it looks like Daniel wants to connect his Mac speaker to the
>*phone handset* mike input, not directly to the line. In this case
>the phone probably provides all the isolation he needs, as well as the
>FCC-approved interface and hook switch and all thet cruft. 
>  The problem in this case is that the solution probably depends on
>the phone you're patching into and what kind of mike it uses.
>I don't know enough about current brands of phones to say if there's
>one overwhelmingly common circuit design (somehow I doubt carbon 
>mikes are still in style) or if there's a way to connect to the phone
>circuit after the first stage of amplification, or whatever...
>
>
>-- 
>email: wiml@u.washington.edu             |  Home:  Seattle, Washington   |
>     (William Lewis)                     |  47 41' 15" N   122 42' 58" W | 
>NeXTmail: wiml@ingalls.cs.washington.edu `-------------------------------'
>        --*-- Member, Coalition to Preserve Semantic Vacuity --*--

Why not try a well known principle, known as 'acoustic coupling'. Putting a 
speaker in front of the phone's microphone (you may isolate it from acoustic 
noise with som styrofoam) will give you a relative easy way to ensure 
correct impedance (volume control), does not violate any rules or laws (FCC 
or otherwise), does not alter the phone, gives you galvanic isolation (no 
risk of frying your Mac) and probably will it give you more than adequate 
sound quality.

Give it a shot.


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