three asterisk voicemailboxes connected to PBX via SIP-tunc. Each mailbox has a "day" and "night" modus, that is configured for all three of them.
copy of relevant part of extensions.conf:
exten => _X.,1,Verbose(Incoming call)
exten => _X.,n,Answer()
exten => _X.,n,GotoIfTime(0:01-23:59,mon-fri,*,*?open)
Skills: asterisk, voip, sip