Tektronix 222 Operator's Manual page 46

What the Controls Do-222 DSO Operators
@
INTEN
-used to adjust the brightness of the display for the best
viewing level.
@
TRlG COM Connector
-
used to provide a trigger common ref-
erence connection point. The TRlG COM connector may be ele-
vated to a maximum of 42 V peak.
If either the EXT TRlG COMM connector or the RS-232
cable is connected to an external earth ground or
external power is applied, the oscilloscope chassis
cannot be elevated.
@
EXTTRIG INPUT Connector
-used to connect an external trig-
ger signal to the oscilloscope.
@
COMM PORT Connector
-
provides an RS-232 compatible
signal port. The limited command set to which the 222 responds
allows waveforms and front-panel setups to be uploaded or
down loaded via the port. Refer to the RS-232 Interface Guide
for operating information and a list of the commands.
@
EXT POWER INPUT Connector
-
used to apply external power
to the instrument. Either a 16 to 20 Vac (at 47 to 400 Hz) or 12 to
28 Vdc power source supplying at least 15 watts or 16 volt-
amperes may be connected to run the oscilloscope and charge
the internal battery. The battery-charger adapter supplied with
the oscilloscope normally produces about 18 Vac, depending
on the mains supply voltage and load current. When external
power is connected, a small indicator
(la)
appears at the right
end of the top readout line.
REV JUN 1989