Playing music through the phone

Elkaid

Member
2003-01-14 1:06 am
Canada
Hi,

I need to build a device for my uncle (musician) that allows him to play music (from cd player, tapes etc.) through the phone so his customers can have a quick idea about the work being made.

I know emails or internet would be easier but he can't use it.

Anyone with ideas ? schematics ?

Thank you very much.
 

Elkaid

Member
2003-01-14 1:06 am
Canada
Thank you,

Keep in mind the inherent limitations of the phone system, namely the bandwidth, which goes from about 300 Hz to 3500 Hz (the sampling rate is 8 kHz).

Thanks. In my case, quality isn't an issue. The goal is to give the customer a "preview" of the project progress so he can give his impressions in real-time.

I don't know what it's like over there, but in the UK it's illegal to connect an unapproved device to the phone line.

Uhhhh... I'm not sure here in Canada but I suppose it's "legal". Maybe that could explain why phone companies are selling "line" insurances in case something blow up between your phone and the telco.
As some says : you're allowed to do anything as long as you don't get caught. Anyway, your point deserves investigation. Thank you.
 

Elkaid

Member
2003-01-14 1:06 am
Canada
Thanks !

I found the following schematic and it would be nice if you could give me your comments about it.

http://home.maine.rr.com/randylinscott/jul98.htm

If I want to be able to speak at the same time as the music plays, can I simply remove R1 ?

Thank you :)
 

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soongsc

Member
2005-03-26 2:31 pm
Taiwan
Elkaid said:
Thanks !

I found the following schematic and it would be nice if you could give me your comments about it.

http://home.maine.rr.com/randylinscott/jul98.htm

If I want to be able to speak at the same time as the music plays, can I simply remove R1 ?

Thank you :)

The circuit looks goo. You might want to see if the CD player has an earphone jack and volume control or not. Normal RCA outputs don't handle 600 ohm impedance well, and you might want to adjust vlume.

If you plug this circuit along with the phone, you would be able to talk while you play when the switch is on.
 

soongsc

Member
2005-03-26 2:31 pm
Taiwan
Most CD outputs like at least 10K. If the CD player has a remote controlled volume, you might just at a buffer. I'm not really sure whether a potentiometer will work or not because I normally don't deal with tranformers in the signal path.

Normally the CD manual would specify what kind of load the RCA output interface requirements are.