The question is whether
DTR pin of
FT232RL becomes active only if the chip is plugged into PC USB host where drivers are installed or whenever the chip is powered on by VCC pin? I couldn't find any particular information on this from datasheet.
FTDI Device Input Output pin States
For Devices: FT232R, FT245R, FT232H, FT2232H, FT4232H & FT2232D
DTR is a Active Low pin. Power on behavior depends on if the chip is set to bus or self powered mode.
Bus powered behavior starts with enumeration in chart, as power comes from the usb host (DTR set to tristate on enumeration, output once active). Since it is active low, I'm assuming it's a voltage high at this point.
Self powered behavior starts at Reset pin being held low (DTR is Tristated). Once the usb connection is added, the USB VDD pulls the reset pin high, and enumeration starts, then active mode.
Suspend refers to Eeprom Setting:
When used in Input Mode, the input pins are pulled to VCCIO via internal 200kΩ resistors. These pins can be programmed to gently pull low during USB suspend (PWREN# = “1”) by setting an option in the internal EEPROM.