Retrieve config files from TXX phones

[lacava]

I was searching for hours and saw that we can telnet the phone to access these files. I try at my side but can't access to the phone.
I found an url address : ip_phone/cgi-bin/ConfigManApp.com?Id=10 to access another options
So I tried different login admin:admin and root:root but nothing work.
How can I connect to the phone via telnet ? Does there is an options to change before ?
I have the latest firmware.

Thanks for your help.