How to make a landline phone ring periodically
Putting a capacitor in series with a phone like that will allow it to ring when the "main distribution facitilty" (I'm assuming you mean FXS, central office, or PABX etc) signals a ring but it will not be able to answer or make calls.  it will not cause it to ring at other times .

For the capacitor 10uF 100V non-polarised sounds about right.

Some phones may behave strangely in this configuration at they require a DC supply for correct on-hook operation. (eg Alcatel TF200 series)

Now, if you have a phone and want to make it ring you need the 90V AC  mentioned in the comments, you can find this on a ringing phone line. or make it using a PABX  or FXS adaptor or a ring generator circuit.