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OPEN COM - a device I/O statement that opens and initializes a
           communications channel for I/O
Syntax
  OPEN "COMn: optlist1 optlist2" [FOR mode] AS [#]filenum [LEN=reclen]
    ■ n is either 1 or 2, and identifies the communications port to be opened
    ■ optlist1 has the following syntax
        [speed][,[parity][,[data][,[stop]]]]
      where the defaults are set for the transmission of text (rather than
      numeric) data. See ◄Details► if you are transmitting numeric data.
──────────────────────────────────────────────────────────────────────────────
speed   bits per second ("baud rate"),│ data  number of data bits per byte,
        default is 300                │       default is 7
parity  type of error checking,       │ stop  number of stop bits after each
        default is Even               │       data byte, default is 1
──────────────────────────────────────────────────────────────────────────────
    ■ optlist2 can specify up to ten other data communications handshaking
      parameters (see ◄Details►).
    ■ filenum, an integer between 1 and 255, is any file number not already
      assigned to an open file
    ■ mode and reclen are ◄Details►