If you ask your average IT professional what a T span is, the usual response will be that it is a 1.5MB connection to the internet. Ask your average telecom tech what a T span is and you will be told it is 24 channels of dial tone! As a VoIP Engineer what a T span is and you should get the answer:, “what do you want it to be”? One of the great challenges of implementing a VoIP solution is the absolute requirement that the implementation team possess an interdisciplinary skill set. The solution demands expertise in a range of specialized skills including IP network, switching, routing, supplementary telephony services , server technology management and application call flow integration. If the user group is going to fully realize the benefits of a VoIP implementation, then each of these specialized areas of technology are going to be necessary to a successful deployment. Traditional telephony vendors are comfortable with all things TDM. They like to punch things down on 66 blocks and use “butt sets” to test for “dial tone”. Network professionals have their area of comfort as to Microsoft or Linux server professionals. Call Center professionals understand caller greeting, salutation, screening, call routing, message acquisition and message retrieval at the application level, but seldom understand the underlying technology. At the end of the day, you can shop the internet and find out who can sell you a shiny new telephone thing cheaper, but finding a team that can execute the delivery of a VoIP solution is worthy of the time you would invest selecting a new CFO! You need to work with a team that can demonstrate proficiency in each of the required discipline and accept responsibility for every aspect of the implementation. From concept to “go live”, the voip solution provider you select  must know the difference between a “dress rehearsal” and a “take”.