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The BlackBerry Internet Service (BIS) account is linked to the carrier billing identifier (SIM, ICCID, IMSI and MSISDN are common billing identifiers). Therefore if a different billing identifier (SIM) and different smartphone is used a new BIS account will be created and each smartphone will manage their own email addresses associated to each smartphone. This means that if you are using 2 smartphones and 2 billing Identifiers (SIMs) you will have 2 separate BIS accounts and will have to integrate your email addresses separately.