This is a small RS232 to RS485 converter project it use for convert RS232 signal level to RS485 level multidrop.It can use with 32 slave to comunicate with PC and embedded systems board for long distance less than 1.2Km( 4000 feet).

 

Specification
- 9-12Vdc power supply
- small size only 2.8" X 1.45 "
- use for RS485 multidrop 2 wire connection.
- Direct connect with PC on DB9 connecter.
- Use RTS signal to control direction .
- 32 Slaves (up to 256 slaves with some transceiver i.e. MAX3088)

 

In the Figure 1 J1 and J2 use for jump R terminate(120) at the end of communication line or last slave.The 75176 use for transceiver.

RTS active (logic 0 or -3 to -15V) when we need to send data .

 

 

Zipped file consist of :
- Schematic
- PCB