This HiSoft BASIC program from my Amiga Format series 'Banging
The Metal' shows a simple way to record time spent online, for
communication software like TERM as well as TCP/IP stacks. It works
by reading the standard serial port hardware. Similar hacks are
possible for other interfaces, if you know their port addresses.

There are two versions - the simple one counts in seconds, while the
other counts in traditional Babylonian hours, minutes and seconds ;-)

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                  595    1233  48.3% -lh5- b86f Nov 29  1999 OnlineTimer.info
[generic]                  665    1072  62.0% -lh5- 3f07 Mar 23  1999 OnlineTimer/OnlineTimer.bas
[generic]                  406     602  67.4% -lh5- 4b76 Nov 29  1999 OnlineTimer/OnlineTimer.bas.info
[generic]                 1432    2561  55.9% -lh5- ccd3 Nov 29  1999 OnlineTimer/OnlineTimer.text
[generic]                  659     750  87.9% -lh5- 0f29 Nov 29  1999 OnlineTimer/OnlineTimer.text.info
[generic]                13658   20136  67.8% -lh5- 4949 Mar 24  1999 OnlineTimer/OnlineTimer1.3
[generic]                  794    1347  58.9% -lh5- ac11 Nov 29  1999 OnlineTimer/OnlineTimer1.3.bas
[generic]                  404     601  67.2% -lh5- caa1 Nov 29  1999 OnlineTimer/OnlineTimer1.3.bas.info
[generic]                  128     338  37.9% -lh5- 8571 Nov 29  1999 OnlineTimer/OnlineTimer1.3.info
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         9 files   18741   28640  65.4%            Dec  1  1999