Dahdi - Timing

[womble1]

Hi,
it takes about 5 seconds for the phones to start ringing with Dahdi and also if the person ringing in hangs up and no one answers it takes 4 sends for the system to realise the caller has hung up…
can we speed these times up ?
asterisk 1.8.6
pbxinaflash purple …
freepbx 2.9

Thanks...