* The scope of the 911 problems caused by wireless and VoIP
In this continuation of our guest commentary by Jim Cavanagh, Jim defines the scope of the problem that both wireless and VoIP bring to the traditional telephony network that was designed assuming that a phone number and a physical location had a one-to-one correspondence – and that any changes in location, such as moving to a new house, happen rarely and are the exception rather than the rule.
Jim explains:
“We all know the drill. Terrorist on the roof across the street? Dial 911. Lost child? Dial 911. Corpse in the swimming pool? Dial 911. We also ‘know’ – a notion reinforced by countless TV shows and movies – that as soon as we have pressed the second ‘1’ of the 9-1-1 dialing sequence that the SWAT helicopters are airborne, the police cruisers and ambulances are rolling and, if need be, the frogmen and submarines are already in the water.
“With the rapid growth of VoIP it is time to consider what happens ‘behind the scenes’ and the changes that VoIP will bring to 911 emergency dialing. In the ‘old days’ of telephony each telephone number had a very strict geographic assignment. Phone number 444-555-6767 mapped directly to 4819 Main Street and, with only a slight allowance for the accuracy of updating phone records, emergency personnel could be dispatched with confidence.
“Wireless brought the first disruption to the geographic assignment as the subscriber was equally as likely to be at 4819 Main Street as they were to be on a highway or at the mall. Wireless location systems known as Phase II compliant are just now being rolled out in many communities across the country. The major benefit of Phase II over Phase I is that Phase I could often locate a person calling for help with no more accuracy than the nearest cell tower. Phase II can pinpoint the location of the caller with far greater accuracy, often to within several feet, under ideal circumstances.
“Most public safety organizations had barely begun solving the wireless problem when VoIP came along. VoIP changes the rules further because in addition to being stationary, nomadic or mobile, a VoIP subscriber is identified by an alphanumeric label rather than a phone number. While the first use of the labels will be the old phone number, ‘4445556767’ for instance, we will increasingly see labels like james.p.cavanagh@telco.net.”
In a later newsletter, we’ll follow up with some answers to how this problem is being solved.
