Patent ID: 8195136

Claim:
A method of providing caller identification information for a plurality of radiotelephone networks operated by a plurality of service providers, the method comprising: providing a registry including a first serial number and a first identification other than the first serial number for a first radiotelephone registered for service with a first service provider operating a first radiotelephone network and a second serial number and a second identification other than the second serial number for a second radiotelephone registered for service with a second service provider operating a second radiotelephone network; accepting a caller identification request from the second radiotelephone network operated by the second service provider when a determination is made that the first radiotelephone is roaming in the second radiotelephone network, wherein the caller identification request includes the first serial number for the first radiotelephone; responsive to accepting the caller identification request, providing a caller identification response to the second radiotelephone network wherein the caller identification response includes the first identification for the first radiotelephone; transmitting billing information from the second radiotelephone network to the first radiotelephone network, the second radiotelephone network determining the first radiotelephone network based on data in the registry; accepting a second caller identification request from the first radiotelephone network operated by the first service provider when a determination is made that the second radiotelephone is roaming in the first radiotelephone network, wherein the second caller identification request includes the second serial number for the second radiotelephone; responsive to accepting the second call identification request, providing a second caller identification response to the first radiotelephone network wherein the second caller identification response includes the second identification for the second radio telephone; transmitting billing information from the first radiotelephone network to the second radiotelephone network, the first radiotelephone network determining the second radiotelephone network based on data in the registry.