covert%covert.DEC@decwrl.dec.com (John R. Covert) (10/31/88)
>There is, of course, a LARGE security problem since the system in which you >are roaming has no way of validating your phone's ESN. ESN = Electronic Serial Number MIN = Mobile Identification Number (the telephone number) MTSO = Mobile Telephone Switching Office MSO = Mobile Service Operator This *was* a large security problem. However, there are now at least two positive validation computer networks operating nationwide (with a gateway between them) which keep a list of the correct ESN/MIN combinations as well as bandit ESNs and allow MTSOs to deny calls to suspect telephones. The systems are PVS (operated by GTE Data Services) and PRV. Generally "B" or wireline carriers use PVS and "A" or non-wireline carriers use PRV. This distinction is not 100% correct, since Southwestern Bell is the wireline carrier in Kansas City but the non-wireline (Cellular One) carrier in Boston and Balto-Wash and PacTel is the wireline in L.A. but the non-wireline in Atlanta (and so on). Not all MSOs are using the validation systems yet, but MSOs who aren't are finding that they are increasingly unable to establish any roaming agreements for their customers, since many MSOs are now refusing to establish roaming agreements with MSOs not served by a validation system. Random side note: It's legitimate for one ESN to have multiple MINs, but a MIN may have one and only one ESN. Thus you can have a phone which supports multiple numbers/systems, but you can't have the same number programmed into more than one phone. /john