VOLTCRAFT 304 Bedienungsanleitung Seite 31

Note!
Whenever you push the button an integrated beeper will give
you acoustic feedback in form of a short "beep".
e) Push-Button °C/°F
With the push-button "°C/°F" you change the measuring unit from
degrees Celsius "°C" to degrees Fahrenheit "°F" and vice versa.
This setting is not kept when the digital thermometer is switched off.
C3 Jack Assignment
a) Measuring Inputs
The measuring jacks T1, T2, T3 and T4 are so-called unipolar (+ and
–) blade contact jacks. You have to connect the K-type temperature
sensors to these jacks if you want to carry out temperature measu-
rements according to the sensor specifications. Please note that the
blade contacts of the connecting plugs are different in breadth.
Warning!
Never try to force the connecting plugs into the jacks when
confused (+ and –)!
The jacks would be irretrievably destroyed and would have to
be replaced.
b) Serial RS–232 Interface
The "OUTPUT" jack is a serial RS-232 interface in 3.5mm stereo
jack format. The assignment is established as follows (connector
plan):
At the back of the connector there is the ground =
GND = reference mass (=reference potential)
In the middle of the connector there is contact
RX = 5V High Input (= data input)
In front at the tip there is contact
TX = 5V High Output (= data output)
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