A standard RS-232 MAX3232 line driver from Maxim performs the TTL-to-RS-232 conversion. The MAX3232 accepts a 5 or 3.3V supply voltage, which is switch-selectable using S 1. D 1 and D 2 block the ...

[Pete] picked up a few RS-232 to TTL conversion boards from an online vendor in China. These boards were supposedly based on the Max3232, a wonderchip that converts the TTL serial to the positive ...