[Asterisk-Dev] FXO - Question

[Angel Diaz]

Hi all:
    Does somebody know how many meters of cable is supported between
Asterisk Digium-FXO cards and the telephone ?

My concern is about the impedances because my cards have to provide 50V to
the phone. Suppose I would like to use in a
building on the floor 25 where is my office and my server is in the floor 6
where is the System Department

Thanks,
Angel