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FTP passive port calculation?

Does anybody know, how the passive port in FTP is calculated? Usually, the server-ip-address is shown in decimal and readable, separated by ",". example:

File Transfer Protocol (FTP)
227 Entering Passive Mode (192,168,145,95,238,20)\r\n
    Response code: Entering Passive Mode (227)
    Response arg: Entering Passive Mode (192,168,145,95,238,20)
    Passive IP address:
    Passive port: 60948

192,168,145,95 = ip-address But passive port bytes 238,20 mean passive-port: 60948