Would like to reduce the number of rings before going to voicemail on our AVAYA phone.

If you read the manual that information is in there.

Change your VMS Cover rings to a larger number.

Programming is done on extension 10 or 11
Press feature 00
Left intercom, Left intercom
#506
mode 1
line 01
number of rings 4
do the same for all lines

If you have a Backup & Restore card you can manually restore the system. If not you will have to restore everything by manually including voicemail greetings and automated attendants.

Turning off voicemail is usually done by the voicemail administrator, they can reset passwords and add or delete a mailbox on an extension. The number of rings before going to voicemail is usually system wide, and that program is changed by whoever programs your phone system.

Sounds like your system lost its programming so now the voicemail ports are just like extensions, they are ringing and picking up. And since the voicemail doesn't know where the phone systemn is, it just transfers all calls to the lowest numbered extension (10)

The system needs to be reprogrammed completely.

Sorry, but it appears that your phone does not offer that option. Need the full manual? You can download/print it here:

http://support.avaya.com/css/P8/documents/100010555

First, call your voice mail. After the messages you will be given a menu to follow. On the Sony Ericsson W350 I went to Personal Options (4) then to Administrative Options (2) and finally Prompt Level (3). After reaching Prompt Level you have the option to shorten or extend the number of rings. At this point I chose to shorten the prompt and then I exitted the system.

You will have to have the admin lengthen the voicemail answer time, i would add another 15-20 seconds.....but this will make all calls ring your phone longer before going to vociemail

By default individual coverage is set to 45 seconds. Ask your phone vendor to reduce it.