asterisk users - Jul 2005 - call forward / and voicemail setting

when i call foreward to an external trunk, the call times out before the 
trunk is able to answer.
I would appreciate some guidance on where in the dialplan I can look to 
extend the wait before considering this a no-reply ?

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also , if anyone cal help me to understand how a user at an extension 
can modify perosnal voicemail id appreciate it .... im told that one can 
dial 0 when in the advanced ivr menu, but i cannot find any 
documentation on how to get to that menu

Thanks in advance

Allan