Frequently Asked Question

All licensing is vendor specific, but the following might provide some answers when calculating licensing needs:

Licensing by IP:

All VoIP phones have an IP address. The only phones that do not have an IP address are cordless handsets that connect to a cordless base. The cordless base has an IP address. In this case, the cordless handsets communicate with the base and the base communicates with the network.

Licensing by Line:

Another related question might be 'how many lines are there'. All Cetis phones only have one line - even two line phones. How is this? This comes down to a meaning of line being derived from analog phones where it was necessary to have a different physical line for each conversation. IP phones are different because all audio and call information is digitized with packets that can be identified differently than packets from a different call and audio stream, so that multiple conversations can come over the same physical line. Hence, when talking about lines and VoIP phones what is generally meant is SIP account. The SIP account is the identity of where the conversation is coming from (the extension number). Many VoIP phones allow more than 1 account so that the conversation can originate from different identities(one for business, one for personal, etc). However, even the same SIP account can have many 'lines' of conversation that would mimic multiple analog lines. Cetis' phones only have 1 account but can use this account for 2 separate conversation streams. However, with licensing, number of lines probably refers to the number of SIP accounts not the actual physical number of conversations from that account that can be placed.

This is also why cordless handsets are not actually considered a 'VoIP' phone but rather just another form of handset for the VoIP base. The difference is that cordless handsets communicate via radio frequency to the base instead of direct wire connection like a corded handset. In this sense, they are an 'accessory' that has no impact on the actual SIP state of the phone. Unlike with the corded handset though, you can have two cordless handsets in conversation at the same time (for 3.x phones) as the cordless chipset in the base can keep track of multiple conversations and then digitize them to go out to the network.