If a remote operator using a BSC RJP dial-up line hangs up the phone, turns off the modem, or is disconnected for any reason before signing off, a data security problem may arise. Under certain conditions, disconnecting without signing off allows another user to connect to the same port and receive data intended for the previous user. To ensure data security, use dedicated BSC RJP lines or use SNA RJP. To minimize data security problems when using BSC RJP dial-up lines, remote operators must sign off before disconnecting.