VIVA offers IP based Converged Communications Solutions. You may contact VIVA for SIP Trunking, IP PBX & PSTN integration, MS OCS & IP PBX integration, Managed VoIP and ''''Secure'''' VoIP.
The function allows you choosing a number that you want in order to
light up during the call to traditional telephones. You can also unlist the
number and it won’t light up.