Is there a code to transfer a call to voice mail instead of ringing the telephone first.

Try xfer(transfer/Conf) dial voicemail dial 2 then the ext number hang up

i.e. my voicemail is 600 so if I wanted to send a call direct to ext 205 mailbox I would dial
xfer(Transfer) 600 2 205

Assuming you have an Emagen or Imagen voice mail, for an outside call you would press transfer>hunt group number of your voicemail (i.e.55)>press 2 and the mailbox number, the key sequence can also be put under a speed dial key on the phone so as all you would have to do is press that button then extension number and the caller is transferred to that extensions mailbox.