![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhx34tTVo-fmg5UJDKV2WDhg5BdtRtXuL3QcpXPVFHIiY0JxNx1EDtlZvaPQzcaizbpQ8Voq5xkGYQKvYeeEeC_LWyt4RXV4m1jnK_uk9rsGcSrSaVg54WWXy4DkMyKms2kVecv1vmSIhk/s400/USB+AVR+Programmer.jpg)
Serasidis says "Nowadays, USB is the most popular connection connection between PC and peripherals such as AVR programmers, printers, scanners etc. For that reason I had to modify my old serial AVR In-System-Programmer (ISP) to work with USB connection. You can say, "use a USB to Serial adaptor to connect your AVR ISP with your PC". Yes, that could be a solution but it would cost me more money than a singe FT232BM chip because I had to include an USB to RS232 adaptor and a power supply for my programmer. (almost €30)".
So, the solution was to replace the two transistors, that were used to adapt the RS-232 voltage levels to TTL voltage levels, with a USB to RS-232 chip such as FT-232BM.
So, the solution was to replace the two transistors, that were used to adapt the RS-232 voltage levels to TTL voltage levels, with a USB to RS-232 chip such as FT-232BM.