Extending ring length on phone

[Spartacus]

How do you extend the ring before it goes to voice mail? I'm on 4 rings but i'd like to extend it to maybe 7 or 8. Tried calling fido about it but they said they don't know.


Im using an iphone 4 by the way. I've also tried looking at this guide but it says theres an error, when adding in the codes.
http://www.arcx.com/sites/GsmFeatures.htm

[kayceeee]

pretty sure its default set to 4 rings. no way of extending it on your end. network controlled.