[rileyecoyote]

I have called into Bell customer service and had recommended to dial *94...4 (number of rings), or try *61 and a long list of * numbers and press send. they either say call not completed, or this function must be done on the handset. I've gone to the manual with no luck finding instructions.

[Bla1ze]

You won't find it in the manual because each voicemail system is largely carrier dependant. Call them back and ask to speak to someone in the tech department who is competent to understand the issue and have them do it on their system side.

[Wezard]

Been a few years back, but I had to get AT&T to change from 4 to 6 six rings on their end. It hasn't reverted through several phone changes.
At the time, they told me it was programmed in their servers by phone #.