not sure if this has been posted, found something useful for checking/setting voicemail configuration (i.e. number of ring before your call directs to mailbox)

QUOTE
Status: *#61#[SEND] The status will report the delay (5, 10, 15.., up to 30) & the number where your calls are diverted if there is no answer.

Activate: **61*[number]**[delay]#[SEND] Use the number that was reported by the status & the delay can be set to (05, 10, 15, 20, 25, or 30) seconds.

Cancel: ##61#[SEND]