Can I control how long the phone rings before a call goes to voicemail
From VoiceMailTel Wiki
You can control how long the phone rings before your calls are directed to voicemail from your online portal account:
-> click on your extension from the left menu -> click on Call Routing -> choose your Forwarding rule (Call Terminal, Forward to another extension or Forward to external numbers) -> increase / decrease the TimeOut (TimeOut is mentioned in seconds)