BotronikS - Final code for all types of Arduino and PC users: -- HOME -- email: botronik@gmail.com
What you need to install or have installed before on your PC: see HERE

RFC8out: RF (radio freq.) Status control of up to 8 Arduino outputs from PC by AT commands...
accessories:
HC-12 : 1-2-3
USBtoTTL: 1 - 2 - 3
HC-12 data
 
 

 
Download the HEX codes below, unpack, and upload to the proper Arduino board (Use a free net tool for example XLoader)
1. ATmega328-16MHz (MINI,NANO,UNO...): Hex-m328
2. AtMega2560 (Mega(ATMEGA2560)........): Hex-m2560

Based on the offered AT commands, you can develop your own communication applications...
TEXT commands (Baud 9600,8 Data bits, None Parity,1 Stop Bit): You can test code (from PC-side) using Termite (select: Append CR):
AT - attention command (return OK)
OxH - set single OUTx at HI(5V) level - example: O1H
OxL - set single OUTx at LO(0V) level - example: O2L
OAH - set all outputs at high (5V) level
OAL - set all outputs at low (0V) level
OA - reading status of all outputs
Ox - reading status of single output x (H=5V L=0V)
 

See corresponding PC SCADA: BScadaID_16out