cx101bg schematic
It will be more simple if you mention the part number of the LCD multimeter
Not for sure only guessing
1 = V+ positive voltage- power supply connection to the meter.
2 = V- negative voltage- power supply connection to the meter.
3 = NC not connected
4 = NC not connected
5 = COM –common=ground
6 = INLO input low Negative measuring input.
7 = INHI input high Positive measuring input.
8 = RFL reference low maybe Connect to COM= 0V ground
9 = RFH reference high
10 = ROH reference out Precision reference voltage output. Connect to RFH for normal operation.
For the decimal point there are two possibilities, first one
11 = D1 connection for dot 1 maybe Connect to 0V to display DP1 (199.9).
12 = D2 connection for dot 2 maybe Connect to 0V to display DP2 (19.99)
13 = D3 connection for dot 3 maybe Connect to 0V to display DP3 (1.999)
second one
11 = D1 connection for dot 1 maybe Connect to V+ to display DP1 (199.9).
12 = D2 connection for dot 2 maybe Connect to V+ to display DP2 (19.99)
13 = D3 connection for dot 3 maybe Connect to V+ to display DP3 (1.999)