LOC

LOC( [#]nbr )

For a file opened as RANDOM this will return the current position of the read/write pointer in the file. Note that the first byte in a file is numbered 1.

For a serial port this will return the number of bytes received and waiting in the receive buffer to be read.
The # is optional.

See also:
CLOSE
CLOSE CONSOLE
INPUT$
LOF
OPEN
OPEN AS CONSOLE