VS 2008 Polling Multiple Sensors & Get serial data..... HELP !!!

Dear Forum,

Hope you are all doing well.
I have been away from programming for a long time and came back on a new project I have been working with VB6 and new to VB.net and would like all your advice / starting idea how to do it in better way?

I have 6 machines installed and wish to get their status like:
Status:
1. Lever UP
2. Lever Down
3. Lever UP and transaction start
3. Lever Down and transaction end with transaction info.

I was thinking how to get their current status because when Lever UP and Transaction Start then it gives Data faster.
So, i planned to start POLLING (Like For .. NEXT loop) in New Thread (if better) and send / get data through serial port through Packets Like:

PC is MASTER>> SEND COMMAND: <STX><ADDR><COMMAND><ETX>

Machine#1 SLAVE: RECEIVED FROM: <STX><ADDR><STATUS DATA><ETX>

Machine#2 SLAVE: RECEIVED FROM: <STX><ADDR><STATUS DATA><ETX>

Machine#3 SLAVE: RECEIVED FROM: <STX><ADDR><STATUS DATA><ETX>


When data receive then update the UI and update the Database etc.

But i am not sure what is the best way to start or any example code for this.

I am looking your best advice in this regard.

Best regards,

Shan