Unknown Transformer----details required

I am planning to tap a telephone line (to feed DTMF decoder as shown in the attachment) through an isolation transformer 600Ω/600Ω of 1:1 type. In our local market it is not readily avail. After a lot of search I have found one Dax 56K DX-56PU modem contains one Transformer .

Find the attachment T1 AASUPREME.
For using that Transformer I have to know the following details.
How can I know the following 4 specifications of the transformer,
Impedance matching (intended value is 600 ohms to 600 ohms)
Frequency response (intended value is 300-3400Hz for Plain Old Telephone System)
Turns ratio (intended value is 1:1)
Does it pass DC current through windings (otherwise I have to use separate capacitors at primary to block DC)

Complete Transformer specification-
aasupreme by
C US 0514
S022168A

I cannot get the specifications through internet.

vinodquilon said:

Complete Transformer specification-
aasupreme by
C US 0514
S022168A

Click to expand...

Did you mean label ?

If you plan to canibalize that transfrormer from the modem and use it on your project; it will work.

As I have stated in your other three threads on this same project, the transformer is not critical. The frequencies used by the modem are the same as your DTMF. The impedance of a modem transformer is designed to be matched to the POTS line, the same as your DTMF receiver. The "primary", if you insist on distinguishing the (nearly identical) windings, is the side connected to the POTS line, the same as your DTMF decoder.

The circuit that you show part of, would pass DC through the windings. This should be avoided. The best thing for you to do is to trace the very simple circuit on that modem and copy it. After you have traced the circuit, please draw it and we can confirm it for you.

PLEASE DO NOT START ANOTHER THREAD FOR THIS PROJECT. USE ONE OF THE FOUR YOU HAVE ALREADY WRITTEN.

I told you before, connect a non-polarised 1μF capacitor in series with the primary and make sure the secondary of the transformer is loaded with 600R otherwise the capacitor could resonate with the transformer's inductance.