dsl filter circuits

[bananaman124]

Has anyone got a good schematic for a ADSL inline phone filter? doesnt seem to be much info out there on them. Thanks for any help

 

[iyung_w]

Simple ADSL filter

Hi, maybe somebody need it, already tried the schematic, it works well to reject modem signal coming out to the phone. Its a low pass filter to reject signal higher than phone voice signal, roughly under 5khz.

Good luck.

**broken link removed**

 

[mneary]

Since the phone line is supposed to be balanced, I would split the 10mH into a pair of 5mH (4.7mH) and the 22 ohm into a pair of 10 ohms.

No good reason to unbalance the phone line unless you really can't afford the extra inductor.

 

[iyung_w]

Since the phone line is supposed to be balanced, I would split the 10mH into a pair of 5mH (4.7mH) and the 22 ohm into a pair of 10 ohms.

No good reason to unbalance the phone line unless you really can't afford the extra inductor.

You right, it is a balance line, the total inductor value is about 10.260mH in series with 22ohm resistor.

details explanation here:
https://www.epanorama.net/documents/telecom/adsl_filter.html

Its not that i can't afford $10 POTS filter, i just build the filters with what i have in my junk box . The phone works fine, so does the modem.

Well, if you do have two 4.7mH in hand, it could be use for the balance line, with the 22ohm in series, and increase the bypass cap to .1uF.

rgds

 

[mvs sarma]

Since the phone line is supposed to be balanced, I would split the 10mH into a pair of 5mH (4.7mH) and the 22 ohm into a pair of 10 ohms.

No good reason to unbalance the phone line unless you really can't afford the extra inductor.

I shall add a point to Mneary's suggestion.

split the capacitor also into two nos of 10nF each and finally the circuit becomes 'O" filter.

The ADSL suppliers infact give a filter also. along with their modem.

**broken link removed**
this site gave a good example and I have tested it working well.

A google search at below address gave a lot of info.

https://www.google.co.in/search?hl=...=result&cd=1&q=adsl+phone+line+filter&spell=1