this small module allows switching of up to 5 LEDs for lighting a model house. Several modules can be connected in parallel and are individually addressed. The protocoll is RS232. Baudrate is 9600. Up to 250 houses with 5 LEDs each can be addressed. The protocol is human readable. The address of the module is stored in the EEPROM of the PIC.
The picture shows an experimental buildup on the PicKit1.
To switch on the light, send H05S02<CR>. the 05 hex is the address of this device, 02 hex means, switch on LED1 and all others off.
The address of a module can also be programmed by RS232. To change the address of the module 05 to 88 simply send H05Paa5588<CR>, so the address will be written to EEPROM