gsm audio interface

[srihari]

hello,
i am using sim300 based gsm modem.i want to interfac gsm audio with pc.i have handset connector and through 1:1 isolation transformer i connected it to pc.
i am able to hear the audio played in the pc thorugh phone but unable to interface with microcphone,some humm noise is coming.how can i perfectly interface with microcphone.

[Binu]

make some pre-amplifier circuit for the microphone.
By the way where do you got the 1:1 isolation transformer, can you get some for me.
Check your mail.

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[srihari]

it's normal 600:600 ohms transforme usualy used in telephone modems ,i got it made personally in a company

[Binu]

how much it cost?
can you some more for me, i can pay it.

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[srihari]

u can get it from digi-key , i stay in india and if ur outside it will cost u more if i ship it

[Binu]

i am also from india.
check your mail

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[srihari]

now the audio interface is working with other modem but its resetting after 10-15 seconds,unble to solve the problem.