How can I get the mobile to ring so I can respond immediatly to a caller's query?

Night service will only control if AA to answer (main greeting) or human, you!.
If people enter extension and it goes straight to vmail then the user invoked that option (Feature 987) which is what you should do when you leave your office.

For all of you that want a real answer here ya go. This isn't something you can change on your phone this has to be changed with your service provider. If you are with AT&T, like I am, then this is the solution for you (link of where I found it below as well). 1. enter *#61*11# and press send/talk on your phone.
2. write down the number your calls are currently forwarded to (usually +1401#######, but not always). this is your voicemail deposit number.
3. decide how long you want the phone to ring in 5 second intervals. the maximum time is 30 seconds. i'd recommend 25 seconds or less, as using 30 may cause you to be billed for a minute of airtime each time someone is forwarded to voicemail.
4. now enter **61*[number from step 2]*11*[number from step 3, use 2 digits]# and press send/talk.

example
voicemail deposit number is +14015551212
you want it to ring for 20 seconds
you would enter **61*+14015551212*11*20# and press send/talk.

if you have trouble with the above procedure, you can always call customer care at 800-331-0500 to change it.
OR QUESTION: How can I adjust the number of times my wireless phone will ring before the caller goes to voicemail? ANSWER: Contact Customer Care at 1-800-331-0500 or dial 611 from your wireless phone to change the amount of time your phone will ring before going to voice mail. The adjustments made by Customer Care are based on the traditional ring heard by the caller, not the unique Ringtone you hear from your phone. I just wanted to add that increasing the ring length to 30 seconds will not cause you to be charged a minute should the caller go to voicemail. This was confirmed by an AT&T technician.
http://forums.att.com/t5/Voice-Mail/Increase-the-number-of-rings-before-a-call-goes-to-the-voicemail/td-p/2576651

Sounds like your service provider(Verizon) has your phone line setup to forward to voicemail on no answer after 2 rings. Call your service provider's customer service number and request that the number of rings for forward no answer be increased to at least 5, then your answer machine can receive and answer your calls after 4 rings but if your line is busy callers can leave a message with your Verizon voicemail service. If you don't want Verizon voicemail to answer any of your calls, you could have them disable the voicemail service. When you call the service provider have a recent bill ready because they may request your account number before they will make any changes.

try transferring the calls from ur mobile to the voicemail when u r not available....
in call settings u might have an option of forwarding the incoming call after so many particular number of rings... forward the calls to ur voicemail numbers using this and then u ll have the numbers in ur recieved calls list.
this might work but is only a temporary solution

Hi, the setting is controlled by your mobile service provider. You will need to ring them and get them to extend the time which it will ring before going to your voicemail. Another option is to totally disable the voicemail function. On your blackberry, enter the phone screen, then press the blackberry logo button to open the menu then select options. Once in the options, select the call forwarding option. Change all settings to "do not forward". Please rate this solution if it helps. Thanks

Completely swith off, then switch on. Wait HTC takes a bit more time to respond. Put on vibration mode or put in full ring and alarm mode. This should work.

Transfer to voice mailbox: Feature 986, dial ext. number of phone and release. Call is transferred to mailbox without ringing the phone.

Hi there, it is possible that you have the G1 set into "always Forward" state, which means when receiving calls the phone will forward the caller to your voicemail.

To Check and change these settings. goto the G1's Home screen, Click the "Menu" button, and then click on "Call settings". Then from here click on "Call Forwarding".

From here, the top setting should say "Always Forward" If this is set to Enabled, click on it and select Disable. This should now allow you to receive calls correctly ! if the Always forward function was disabled already, i would suggest calling T-Mobiles Customer support line to see if they have a remedy to this situation !

Hope this helps ?!

check in settings/phone to see if you have maybe turned on call forwarding and it is being forwarded automatic to your voicemail box number