By Allen David Niven
SIP trunking allows telemessaging call centers to eliminate toll-free numbers that clients are forwarded to, while maintaining a national service area. Instead of forwarding calls to toll-free numbers, clients forward to local DID numbers, wherever they are. There is no per-minute charge for the incoming call, so the cost savings are huge, the service often paying for itself within a few months.
If the call center equipment does not support SIP trunking natively, a T-1 gateway must be used. Such gateways cost about $2500 per T-1 and are manufactured by companies such as Cisco, Linksys, and Quintum. They have only two ports: an RJ-48 that connects to the T-1 port on the call center equipment and an RJ-45 that connects to the Internet.
Few companies that sell SIP trunking actually own the points of presence nationally themselves – most are resellers. Usually, the more thorough their nationwide coverage is, the higher the price per trunk. Niche players can often give good coverage at great rates. Contracting with more than one provider can produce a good mix of niche and nationwide coverage.
Companies that sell SIP trunking qualify as CLECs – competitive local exchange carriers. This means that by law they must allow numbers to be ported. The call center fills out a form for local number portability, and the numbers must be transferred within thirty days.
Allen David Niven is CEO of GlobalFone.
[From Connection Magazine – June 2008]