Acom 2000A Operating Manual page 23

The amplifier will wait for you to apply between 10 and 20W continuous (CW) carrier signal on
the desired frequency. If you don't begin transmitting within 40 seconds, the amplifier will return
back to the MAIN menu.
The automatic matching process starts the moment power remains constant within the indicated
boundaries. This is shown by the bottom bar graph, which indicates the applied input power
and glows in green:
If the drive power is less than 10W or greater than 20W, the yellow arrows will remind you to
correspondingly increase or decrease the drive:
The antenna impedance matching process is completed in less than 3 seconds and "AUTO
TUNE COMPLETED PLEASE REMOVE DRIVE message is displayed as shown in figure 4-5
and the letter "S" is being sent in CW:
Fig.4-5 RCU display - end of AUTO TUNE
N O T E
If the KEY-OUT control is used (see S.2-4e), the above message will be skipped.
If for some reason matching cannot be accomplished successfully (for example excessive VSWR
or unstable drive power during tune-up), the process ends up with the choice of DEF-tuning
and you will hear "K" being sent in CW.
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